CHAPTER XXIII.

THE SUCCESSION OF LIFE UPON THE GLOBE.

In conclusion, it may not be out of place if we attempt to summarise, in the briefest possible manner, some of the principal results which may be deduced as to the succession of life upon the earth from the facts which have in the preceding portion of this work been passed in review. That there was a time when the earth was void of life is universally admitted, though it may be that the geological record gives us no direct evidence of this. That the globe of to-day is peopled with innumerable forms of life whose term of existence has been, for the most part, but as it were of yesterday, is likewise an assertion beyond dispute. Can we in any way connect the present with the remote past, and can we indicate even imperfectly the conditions and laws under which the existing order was brought about? The long series of fossiliferous deposits, with their almost countless organic remains, is the link between what has been and what is; and if any answer to the above question can be arrived at, it will be by the careful and conscientious study of the facts of Palæontology. In the present state of our knowledge, it may be safely said that anything like a dogmatic or positive opinion as to the precise sequence of living forms upon the globe, and still more as to the manner in which this sequence may have been brought about, is incapable of scientific proof. There are, however, certain general deductions from the known facts which may be regarded as certainly established.

In the first place, it is certain that there has been a _succession_ of life upon the earth, different specific and generic types succeeding one another in successive periods. It follows from this, that the animals and plants with which we are familiar as living, were not always upon the earth, but that they have been preceded by numerous races more or less differing from them. What is true of the species of animals and plants, is true also of the higher zoological divisions; and it is, in the second place, quite certain that there has been a similar _succession_ in the order of appearance of the primary groups ("sub-kingdoms," "classes," &c.) of animals and vegetables. These great groups did not all come into existence at once, but they made their appearance successively. It is true that we cannot be said to be certainly acquainted with the first _absolute_ appearance of any great group of animals. No one dare assert positively that the apparent first appearance of Fishes in the Upper Silurian is really their first introduction upon the earth: indeed, there is a strong probability against any such supposition. To whatever extent, however, future discoveries may push back the first advent of any or of all of the great groups of life, there is no likelihood that anything will be found out which will materially alter the _relative_ succession of these groups as at present known to us. It is not likely, for example, that the future has in store for us any discovery by which it would be shown that Fishes were in existence before Molluscs, or that Mammals made their appearance before Fishes. The sub-kingdoms of Invertebrate animals were all represented in Cambrian times--and it might therefore be inferred that _these_ had all come simultaneously into existence; but it is clear that this inference, though incapable of actual disproof, is in the last degree improbable. Anterior to the Cambrian is the great series of the Laurentian, which, owing to the metamorphism to which it has been subjected, has so far yielded but the singular _Eozoön_. We may be certain, however, that others of the Invertebrate sub-kingdoms besides the Protozoa were in existence in the Laurentian period; and we may infer from known analogies that they appeared successively, and not simultaneously.

When we come to smaller divisions than the sub-kingdoms--such as classes, orders, and families--a similar succession of groups is observable. The different classes of any given sub-kingdom, or the different orders of any given class, do not make their appearance together and all at once, but they are introduced upon the earth in _succession_. More than this, the different classes of a sub-kingdom, or the different orders of a class, _in the main succeed one another in the relative order of their zoological rank--the lower groups appearing first and the higher groups last_. It is true that in the Cambrian formation--the earliest series of sediments in which fossils are abundant--we find numerous groups, some very low, others very high, in the zoological scale, which _appear_ to have simultaneously flashed into existence. For reasons stated above, however, we cannot accept this appearance as real; and we must believe that many of the Cambrian groups of animals really came into being long before the commencement of the Cambrian period. At any rate, in the long series of fossiliferous deposits of later date than the Cambrian the above-stated rule holds good as a broad generalisation--that the lower groups, namely, precede the higher in point of time; and though there are apparent exceptions to the rule, there are none of such a nature as not to admit of explanation. Some of the leading facts upon which this generalisarion is founded will be enumerated immediately; but it will be well, in the first place, to consider briefly what we precisely mean when we speak of "higher" and "lower" groups.

It is well known that naturalists are in the habit of "classifying" the innumerable animals which now exist upon the globe; or, in other words, of systematically arranging them into groups. The precise arrangement adopted by one naturalist may differ in minor details from that adopted by another; but all are agreed as to the fundamental points of classification, and all, therefore, agree in placing certain groups in a certain sequence. What, then, is the principle upon which this sequence is based? Why, for example, are the Sponges placed below the Corals; these below the Sea-urchins; and these, again, below the Shell-fish? Without entering into a discussion of the principles of zoological classification, which would here be out of place, it must be sufficient to say that the sequence in question is based upon the _relative type of organisation_ of the groups of animals classified. The Corals are placed above the Sponges upon the ground that, regarded as a whole, the _plan or type of structure_ of a Coral is more complex than that of a Sponge. It is not in the slightest degree that the Sponge is in any respect less highly organised or less perfect, as a Sponge, than is the Coral as a Coral. Each is equally perfect in its own way; but the structural pattern of the Coral is the highest, and therefore it occupies a higher place in the zoological scale. It is upon this principle, then, that the primary subdivisions of the animal kingdom (the so-called "sub-kingdoms") are arranged in a certain order. Coming, again, to the minor subdivisions (classes, orders, &c.) of each sub-kingdom, we find a different but entirely analogous principle employed as a means of classification. The numerous animals belonging to any given sub-kingdom are formed upon the same fundamental plan of structure; but they nevertheless admit of being arranged in a regular series of groups. All the Shell-fish, for example, are built upon a common plan, this plan representing the ideal Mollusc; but there are at the same time various groups of the _Mollusca_, and these groups admit of an arrangement in a given sequence. The principle adopted in this case is simply of _the relative elaboration of the common type_. The Oyster is built upon the same ground-plan as the Cuttle-fish; but this plan is carried out with much greater elaboration, and with many more complexities, in the latter than in the former: and in accordance with this, the _Cephalopoda_ constitute a higher group than the Bivalve Shell-fish. As in the case of superiority of structural type, so in this case also, it is not in the least that the Oyster is an _imperfect_ animal. On the contrary, it is just as perfectly adapted by its organisation to fill its own sphere and to meet the exigencies of its own existence as is the Cuttle-fish; but the latter lives a life which is, physiologically, higher than the former, and its organisation is correspondingly increased in complexity.

This being understood, it may be repeated that, in the main, the succession of life upon the globe in point of _time_ has corresponded with the relative order of succession of the great groups of animals in _zoological rank_; and some of the more striking examples of this may be here alluded to. Amongst the _Echinoderms_, for instance, the two orders generally admitted to be the "lowest" in the zoological scale--namely, the _Crinoids_ and the _Cystoids_--are likewise the oldest, both, appearing in the Cambrian, the former slowly dying out as we approach the Recent period, and the latter disappearing wholly before the close of the Palæozoic period. Amongst the _Crustaceans_, the ancient groups of the Trilobites, Ostracodes, Phyllopods, Eurypterids, and Limuloids, some of which exist at the present day, are all "low" types; whereas the highly-organised Decapods do not make their appearance till near the close of the Palæozoic epoch, and they do not become abundant till we reach Mesozoic times. Amongst the _Mollusca_, those Bivalves which possess breathing-tubes (the "siphonate" Bivalves) are generally admitted to be higher than those which are destitute of these organs (the "asiphonate" Bivalves); and the latter are especially characteristic of the Palæozoic period, whilst the former abound in Mesozoic and Kainozoic formations. Similarly, the Univalves with breathing-tubes and a corresponding notch in the mouth of the shell ("siphonostomatous" Univalves) are regarded as higher in the scale than the round-mouthed vegetable-eating Sea-snails, in which no respiratory siphons exist ("holostomatous" Univalves); but the latter abound in the Palæozoic rocks--whereas the former do not make their appearance till the Jurassic period, and their higher groups do not seem to have existed till the close of the Cretaceous. The _Cephalopods_, again--the highest of all the groups of Mollusca--are represented in the Palæozoic rocks exclusively by Tetrabranchiate forms, which constitute the lowest of the two orders of this class; whereas the more highly specialised Dibranchiates do not make their appearance till the commencement of the Mesozoic. The Palæozoic Tetrabranchiates, also, are of a much simpler type than the highly complex _Ammonitidoe_ of the Mesozoic.

Similar facts are observable amongst the _Vertebrate animals_. The Fishes are the lowest class of Vertebrates, and they are the first to appear, their first certain occurrence being in the Upper Silurian; whilst, even if the Lower Silurian and Upper Cambrian "Conodonts" were shown to be the teeth of Fishes, there would still remain the enormously long periods of the Laurentian and Lower Cambrian, during which there were Invertebrates, but no Vertebrates. The _Amphibians_, the next class in zoological order, appears later than the Fishes, and is not represented till the Carboniferous; whilst its highest group (that of the Frogs and Toads) does not make its entrance upon the scene till Tertiary times are reached. The class of the _Reptiles_, again, the next in order, does not appear till the Permian, and therefore not till after Amphibians of very varied forms had been in existence for a protracted period. The _Birds_ seem to be undoubtedly later than the Reptiles; but, owing to the uncertainty as to the exact point of their first appearance, it cannot be positively asserted that they preceded Mammals, as they should have done. Finally, the Mesozoic types of _Mammals_ are mainly, if not exclusively, referable to the _Marsupials_, one of the lowest orders of the class; whilst the higher orders of the "Placental" Quadrupeds are not with certainty known to have existed prior to the commencement of the Tertiary period.

Facts of a very similar nature are offered by the succession of Plants upon the globe. Thus the vegetation of the Palæozoic period consisted principally of the lowly-organised groups of the Cryptogamous or Flowerless plants. The Mesozoic formations, up to the Chalk, are especially characterised by the naked-seeded Flowering plants--the Conifers and the Cycads; whilst the higher groups of the Angiospermous Exogens and Monocotyledons characterise the Upper Cretaceous and Tertiary rocks.

Facts of the above nature--and they could be greatly multiplied--seem to point clearly to the existence of some law of progression, though we certainly are not yet in a position to formulate this law, or to indicate the precise manner in which it has operated. Two considerations, also, must not be overlooked. In the first place, there are various groups, some of them highly organised, which make their appearance at an extremely ancient date, but which continue throughout geological time almost unchanged, and certainly unprogressive. Many of these "persistent types" are known--such as various of the _Foraminifera_, the _Linguloe_, the _Nautili_, &c.; and they indicate that under given conditions, at present unknown to us, it is possible for a life-form to subsist for an almost indefinite period without any important modification of its structure. In the second place, whilst the facts above mentioned point to some general law of progression of the great zoological groups, it cannot be asserted that the primeval types _of any given group_ are necessarily "lower," zoologically speaking, than their modern representatives. Nor does this seem to be at all necessary for the establishment of the law in question. It cannot be asserted, for example, that the Ganoid and Placoid Fishes of the Upper Silurian are in themselves less highly organised than their existing representatives; nor can it even be asserted that the Ganoid and Placoid orders are low _groups_ of the class _Pisces_. On the contrary, they are high groups; but then it must be remembered that these are probably not really the first Fishes, and that if we meet with Fishes at some future time in the Lower Silurian or Cambrian, these may easily prove to be representatives of the lower orders of the class. This question cannot be further entered into here, as its discussion could be carried out to an almost unlimited length; but whilst there are facts pointing both ways, it appears that at present we are not justified in asserting that the earlier types of each group--so far as these are known to us, or really are without predecessors--are _necessarily_ or _invariably_ more "degraded" or "embryonic" in their structure than their more modern representatives.

It remains to consider very briefly how far Palæontology supports the doctrine of "Evolution," as it is called; and this, too, is a question of almost infinite dimensions, which can but be glanced at here. Does Palæontology teach us that the almost innumerable kinds of animals and plants which we know to have successively flourished upon the earth in past times were produced separately and wholly independently of each other, at successive periods? or does it point to the theory that a large number of these supposed distinct forms, have been in reality produced by the slow modification of a comparatively small number of primitive types? Upon the whole, it must be unhesitatingly replied that the evidence of Palæontology is in favour of the view that the succession of life-forms upon the globe has been to a large extent regulated by some orderly and constantly-acting law of modification and evolution. Upon no other theory can we comprehend how the fauna of any given formation is more closely related to that of the formation next below in the series, and to that of the formation next above, than to that of any other series of deposits. Upon no other view can we comprehend why the Post-Tertiary Mammals of South America should consist principally of Edentates, Llamas, Tapirs, Peccaries, Platyrhine Monkeys, and other forms now characterising this continent; whilst those of Australia should be wholly referable to the order of Marsupials. On no other view can we explain the common occurrence of "intermediate" or "transitional" forms of life, filling in the gaps between groups now widely distinct.

On the other hand, there are facts which point clearly to the existence of some law other than that of evolution, and probably of a deeper and more far-reaching character. Upon no theory of evolution can we find a satisfactory explanation for the constant introduction throughout geological time of new forms of life, which do not appear to have been preceded by pre-existent allied types; The Graptolites and Trilobites have no known predecessors, and leave no known successors. The Insects appear suddenly in the Devonian, and the Arachnides and Myriapods in the Carboniferous, under well-differentiated and highly-specialised types. The Dibranchiate Cephalopods appear with equal apparent suddenness in the older Mesozoic deposits, and no known type of the Palæozoic period can be pointed to as a possible ancestor. The _Hippuritidoe_ of the Cretaceous burst into a varied life to all appearance almost immediately after their first introduction into existence. The wonderful Dicotyledonous flora of the Upper Cretaceous period similarly surprises us without any prophetic annunciation from the older Jurassic.

Many other instances could be given; but enough has been said to show that there is a good deal to be said on both sides, and that the problem is one environed with profound difficulties. One point only seems now to be universally conceded, and that is, that the record of life in past time is not interrupted by gaps other than those due to the necessary imperfections of the fossiliferous series, to the fact that many animals are incapable of preservation in a fossil condition, or to other causes of a like nature. All those who are entitled to speak on this head are agreed that the introduction of new and the destruction of old species have been slow and gradual processes, in no sense of the term "catastrophistic." Most are also willing to admit that "Evolution" has taken place in the past, to a greater or less extent, and that a greater or less number of so-called species of fossil animals are really the modified descendants of pre-existent forms. _How_ this process of evolution has been effected, to what extent it has taken place, under what conditions and laws it has been carried out, and how far it may be regarded as merely auxiliary and supplemental to some deeper law of change and progress, are questions to which, in spite of the brilliant generalisations of Darwin, no satisfactory answer can as yet be given. In the successful solution of this problem--if soluble with the materials available to our hands--will lie the greatest triumph that Palæontology can hope to attain; and there is reason to think that, thanks to the guiding-clue afforded by the genius of the author of the 'Origin of Species,' we are at least on the road to a sure, though it may be a far-distant, victory.

APPENDIX.

TABULAR VIEW OF THE CHIEF DIVISIONS OF THE ANIMAL KINGDOM.

(Extinct groups are marked with an asterisk. Groups not represented at all as fossils are marked with two asterisks.)

INVERTEBRATE ANIMALS.

SUB-KINGDOM I.--PROTOZOA.

Animal simple or compound; body composed of "sarcode," not definitely segmented; no nervous system; and no digestive apparatus, beyond occasionally a mouth and gullet.

CLASS I. GREGARINIDÆ.** CLASS II. RHIZOPODA. _Order_ 1. _Monera_.** " 2. _Amoebea_.** " 3. _Foraminifera_. " 4. _Radiolaria_ (Polycystines, &c.) " 5. _Spongida_ (Sponges). CLASS III. INFUSORIA.**

SUB-KINGDOM II.--COELENTERATA.

Animal simple or compound; body-wall composed of two principal layers; digestive canal freely communicating with the general cavity of the body; no circulating organs, and no nervous system or a rudimentary one; mouth surrounded by tentacles, arranged, like the internal organs, in a "radiate" or star-like manner.

CLASS I. HYDROZOA. _Sub-class_ 1. _Hydroida_ ("Hydroid Zoophytes"). _Ex._ Fresh-water Polypes,** Pipe-corallines (_Tubularia_), Sea-Firs (_Sertularia_). _Sub-class_ 2. _Siphonophora_** ("Oceanic Hydrozoa"). _Ex_. Portuguese Man-of-war (_Physalia_). _Sub-class_ 3. _Discophora_ ("Jelly-fishes"). Only known as fossils by impressions of their stranded carcasses. _Sub-class_ 4. _Lucernarida_ ("Sea-blubbers"). Also only known as fossils by impressions left in fine-grained strata. _Sub-class_ 5. _Graptolitidoe_* ("Graptolites"). CLASS II. ACTINOZOA. _Order_ 1. _Zoantharia_. _Ex_. Sea-anemones** (_Actinidoe_), Star-corals (_Astroeidoe_). _Order_ 2. _Alcyonaria_. _Ex_. Sea-pens (_Pennatula_), Organ-pipe Coral (_Tubipora_), Red Coral (_Corallium_). _Order_ 3. _Rugosa_ ("Rugose Corals"). " 4. _Ctenophora_.** _Ex_. Venus's Girdle (_Cestum_).

SUB-KINGDOM III.--ANNULOIDA.

Animals in which the digestive canal is completely shut off from the cavity of the body; a distinct nervous system; a system of branched "water-vessels," which usually communicate with the exterior. Body of the adult often "radiate," and never composed of a succession of definite rings.

CLASS I. ECHINODERMATA. _Order_ 1. _Crinoidea_ ("Sea-lilies"). _Ex_. Feather-star (_Comatula_), Stone-lily (_Encrinus_*). _Order_ 2. _Blastoidea_* ("Pentremites"). " 3. _Cystoidea_* ("Globe-lilies"). " 4. _Ophiuroidea_ ("Brittle-stars"). _Ex_. Sand-stars (_Ophiura_), Brittle-stars (_Ophiocoma_). _Order_ 5. _Asteroidea_ ("Star-fishes"). Ex. Cross-fish (_Uraster_), Sun-star (_Solaster_). _Order_ 6. _Echinoidea_ ("Sea-urchins"). Ex. Sea-eggs (_Echinus_), Heart-urchins (_Spatangus_). _Order_ 7. _Holothuroidea_ ("Sea-cucumbers"). _Ex_. Trepangs (_Holothuria_). CLASS II. SCOLECIDA** (Intestinal Worms, Wheel Animalcules, &c.)

SUB-KINGDOM IV.--ANNULOSA.

Animal composed of numerous definite segments placed one behind the other; nervous system forming a knotted cord placed along the lower (ventral) surface of the body.

_Division A. Anarthropoda_. No jointed limbs.

CLASS I. GEPHYREA** ("Spoon-worms"). CLASS II. ANNELIDA. ("Ringed-worms"). _Ex_. Leeches** (_Hirudinea_), Earthworms** (_Oligochoeta_), Tube-worms (_Tubicola_), Sea-worms and Sea-centipedes (_Errantia_). CLASS III. CHÆTOGNATHA** ("Arrow-worms").

_Division B. Arthropoda or Articulata_. Limbs jointed to the body.

CLASS I. CRUSTACEA ("Crustaceans"). _Ex_. Barnacles and Acorn-shells (_Cirripedia_), Water-fleas (_Ostracoda_), Brine-shrimps and Fairy-shrimps (_Phyllopoda_), Trilobites* (_Trilobita_), King-crabs and Eurypterids* (_Merostomata_), Wood-lice and Slaters (_Isopoda_), Sand-hoppers (_Amphipoda_), Lobsters, Shrimps, Hermit-crabs, and Crabs (_Decapoda_). CLASS II. ARACHNIDA. _Ex._ Mites (_Acarina_), Scorpions (_Pedipalpi_), Spiders (_Araneida_). CLASS III. MYRIAPODA. _Ex._ Centipedes (_Chilopoda_), Millipedes and Galley-worms (_Chilignatha_). CLASS IV. INSECTA ("Insects"). _Ex_. Field-bugs (_Hemiptera_); Crickets, Grasshoppers, &c. (_Orthoptera_); Dragon-flies and May-flies (_Neuroptera_); Goats and House-flies (_Diptera_); Butterflies and Moths (_Lepidoptera_); Bees, Wasps, and Ants (_Hymenoptera_); Beetles (_Coleoptera_).

SUB-KINGDOM V.--MOLLUSCA.

Animal soft-bodied, generally with a hard covering or shell; no distinct segmentation of the body; nervous system of scattered masses.

CLASS I. POLYZOA ("Sea-Mosses"). _Ex_. Sea-mats (_Flustra_), Lace-corals (_Fenestellidoe_*). CLASS II. TUNICATA** ("Tunicaries"). _Ex_. Sea-squirts (_Ascidia_). CLASS III. BRACHIOPODA ("Lamp-shells"). _Ex_. Goose-bill Lamp-shell (_Lingula_). CLASS IV. LAMELLIBRANCHIATA ("Bivalves"). _Ex_. Oyster (_Ostrea_), Mussel (_Mytilus_), Scallop (_Pecten_), Cockle (_Cardium_). CLASS V. GASTEROPODA ("Univalves"). _Ex_. Whelks (_Buccinum_), Limpets (_Patella_), Sea-slugs** (_Doris_), Land-snails (_Helix_). CLASS VI. PTEROPODA ("Winged Snails"). Ex. _Hyalea, Cleodora_. CLASS VII. CEPHALOPODA ("Cuttle-fishes"). _Ex_. Calamary (_Loligo_), Poulpe (_Octopus_), Paper Nautilus (_Arganauta_), Pearly Nautilus (_Nautilus_), Belemnites,* Orthoceratites,* Ammonites.*

VERTEBRATE ANIMALS.

SUB-KINGDOM VI.--VERTEBRATA.

Body composed of definite segments arranged longitudinally one behind the other; main masses of the nervous system placed dorsally; a backbone or "vertebral column" in the majority.

CLASS I. PISCES ("Fishes"). _Ex_. Lancelet** (_Amphioxus_); Lampreys and Hag-fishes (_Marsipobranchii_**); Herring, Salmon, Perch, &c. (_Teleostei_ or "Bony Fishes"); Gar-pike, Sturgeon, &c. (_Ganoidei_); Sharks, Dog-fishes, Rays, &c. (_Elasmobranchii_ or "Placoids"). CLASS II. AMPHIBIA ("Amphibians"). Ex. _Labyrinthodontia_,* Cæcilians,** Newts and Salamanders (_Urodela_), Frogs and Toads (_Anoura_). CLASS III. REPTILIA ("Reptiles"). Ex. _Deinosauria_,* _Pterosauria_,* _Anomodontia_,* Plesiosaurs (_Sauropterygia_*), Ichthyosaurs (_Ichthyopterygia_*), Tortoises and Turtles (_Chelonia_), Snakes (_Ophidia_), Lizards (_Lacertilia_), Crocodiles (_Crocodilia_). CLASS IV. AVES ("Birds"). _Ex_. Toothed Birds (_Odontornithes_*); Lizard-tailed Birds (_Archoeopteryx_*); Ducks, Geese, Gulls, &c. (_Natatores_); Storks, Herons, Snipes, Plovers, &c. (_Grallatores_); Ostrich, Emeu, Cassowary, Dinornis,* Æpiornis,* &c. (_Cursores_); Fowls, Game Birds, and Doves (_Rasores_); Cuckoos, Woodpeckers, Parrots, &c. (_Scansores_); Crows, Starlings, Finches, Hummingbirds, Swallows, &c. (_Insessores_); Owls, Hawks, Eagles, Vultures (_Raptores_). CLASS V. MAMMALIA ("Quadrupeds"). _Ex_. Duck-mole and Spiny Ant-eater (_Monotremata_**); Kangaroos, Phalangers, Opossums, Tasmanian Devil, &c. (_Marsupialia_); Sloths, Ant-eaters, Armadillos (_Edentata_); Manatees and Dugongs (_Sirenia_); Whales, Dolphins, Porpoises (_Cetacea_); Rhinoceros, Tapir, Horses, Hippopotamus, Pigs, Camels and Llamas, Giraffes, Deer, Antelopes, Sheep, Goats, Oxen (_Ungulata_); Hyrax (_Hyracoidea_**); Elephants, Mastodon,* Deinotherium* (_Proboscidea_); Seals, Walrus, Bears, Dogs, Wolves, Cats, Lions, Tigers, &c. (_Carnivora_); Hares, Rabbits, Porcupines, Beavers, Rats, Mice, Lemmings, Squirrels, Marmots, &c. (_Rodentia_); Bats (_Cheiroptera_); Moles, Shrew-mice, Hedgehogs (_Insectivora_); Lemurs, Spider-monkeys, Macaques, Baboons, Apes (_Quadrumana_); Man (_Bimana_).

GLOSSARY.

ABDOMEN (Lat. _abdo_, I conceal). The posterior cavity of the body, containing the intestines and others of the viscera. In many Invertebrates there is no separation of the body-cavity into thorax and abdomen, and it is only in the higher _Annulosa_ that a distinct abdomen can be said to exist.

ABERRANT (Lat. _aberro_, I wander away). Departing from the regular type.

ABNORMAL (Lat. _ab_, from; _norma_, a rule). Irregular; deviating from the ordinary standard.

ACRODUS (Gr. _akros_, high; _odous_, tooth). A genus of the Cestraciont fishes, so called from the elevated teeth.

ACROGENS (Gr. _akros_, high; _gennao_, I produce). Plants which increase in height by additions made to the summit of the stem by the union of the bases of the leaves.

ACROTRETA (Gr. _akros_, high; _tretos_, pierced). A genus of Brachiopods, so called from the presence of a foramen at the summit of the shell.

ACTINOCRINUS (Gr. _aktin_, a ray; _krinon_, a lily). A genus of Crinoids.

ACTINOZOA (Gr. _aktin_, a ray; and _zoön_, an animal). That division of the _Coelenterata_ of which the Sea-anemones may be taken as the type.

ÆGLINA (_Æglé_, a sea-nymph). A genus of Trilobites.

ÆPIORNIS (Gr. _aipus_, huge; _ornis_, bird). A genus of gigantic Cursorial birds.

AGNOSTUS (Gr. _a_, not; _gignosko_, I know). A genus of Trilobites.

ALCES (Lat. _alces_, elk). The European Elk or Moose.

ALECTO (the proper name of one of the Furies). A genus of _Polyzoa_.

ALETHOPTERIS (Gr. _alethes_, true; _pteris_, fern). A genus of Ferns.

ALGÆ. (Lat. _alga_, a marine plant). The order of plants comprising the Sea-weeds and many fresh-water plants.

ALVEOLUS (Lat. _alvus_, belly). Applied to the sockets of the teeth.

AMBLYPTERUS (Gr. _amblus_, blunt; _pteron_, fin). An order of Ganoid Fishes.

AMBONYCHIA (Gr. _ambon_, a boss; _onux_, claw). A genus of Palæozoic Bivalves.

AMBULACRA (Lat. _ambulacrum_, a place for walking). The perforated spaces or "avenues" through which are protruded the tube-feet, by means of which locomotion is effected in the _Echinodermata_.

AMMONITIDÆ. A family of Tetrabranchiate Cephalopods, so called from the resemblance of the shell of the type-genus, _Ammonites_, to the horns of the Egyptian God, Jupiter-Ammon.

AMORPHOZOA (Gr. _a_, without; _morphe_, shape; _zoön_, animal). A name sometimes used to designate the _Sponges_.

AMPHIBIA (Gr. _amphi_, both; _bios_, life). The Frogs, Newts, and the like, which have gills when young, but can always breathe air directly when adult.

AMPHICYON (Gr. _amphi_, both--implying doubt; _kuon_, dog). An extinct genus of _Carnivora_.

AMPHILESTES (Gr. _amphi_, both; _lestes_, a thief). A genus of Jurassic Mammals.

AMPHISPONGIA (Gr. _amphi_, both; _spoggos_, sponge). A genus of Silurian sponges.

AMPHISTEGINA (Gr. _amphi_, both; _stegé_, roof). A genus of _Foraminifera_.

AMPHITHERIUM (Gr. _amphi_, both; _therion_, beast). A genus of Jurassic Mammals.

AMPHITRAGULUS (Gr. _amphi_, both; dim. of _tragos_, goat). An extinct genus related to the living Musk-deer.

AMPLEXUS (Lat. an Ambrace). A genus of Rugose Corals.

AMPYX (Gr. _ampux_, a wreath or wheel). A genus of Trilobites.

ANARTHROPODA (Gr. _a_, without; _arthros_, a joint; _pous_, foot). That division of _Annulose_ animals in which there are no articulated appendages.

ANCHITHERIUM (Gr. _agchi_, near; _therion_, beast). An extinct genus of Mammals.

ANCYLOCERAS (Gr. _agkulos_, crooked; _ceras_, horn). A genus of _Ammonitidoe_.

ANCYLOTHERIUM (Gr. _agkulos_, crooked; _therion_, beast). An extinct genus of Edentate Mammals.

ANDRIAS (Gr. _andrias_, image of man). An extinct genus of tailed Amphibians.

ANGIOSPERMS (Gr. _angeion_, a vessel; _sperma_, seed). Plants which have their seeds enclosed in a seed-vessel.

ANNELIDA (a Gallicised form of _Annulata_). The Ringed Worms, which form one of the divisions of the _Anarthropoda_.

ANNULARIA (Lat. _annulus_, a ring). A genus of Palæozoic plants, with leaves in whorls.

ANNULOSA (Lat. _annulus_). The sub-kingdom comprising the _Anarthropoda_ and the _Arthropoda_ or _Articulata_, in all of which the body is more or less evidently composed of a succession of rings.

ANOMODONTIA (Gr. _anomos_, irregular; _odous_, tooth). An extinct order of Reptiles, often called _Dicynodontia_.

ANOMURA (Gr. _anomos_, irregular; _oura_, tail). A tribe of Decapod _Crustacea_, of which the Hermit-crab is the type.

ANOPLOTHERIDÆ (Gr. _anoplos_, unarmed; _ther_, beast). A family of Tertiary Ungulates.

ANOURA (Gr. _a_, without; _oura_, tail). The order of _Amphibia_ comprising the Frogs and Toads, in which the adult is destitute of a tail. Often, called _Batrachia_.

ANTENNÆ (Lat. _antenna_, a yard-arm). The jointed horns or feelers possessed by the majority of the _Articulata_.

ANTENNULES (dim. of _Antennoe_). Applied to the smaller pair of antennæ in the _Crustacea_.

ANTHRACOSAURUS (Gr. _anthrax_, coal; _saura_, lizard). A genus of Labyrinthodont Amphibians.

ANTHRAPALÆMON (Gr. _anthrax_, coal; _paloemon_, a prawn--originally a proper name). A genus of long-tailed Crustaceans from the Coal-measures.

ANTLERS. Properly the branches of the horns of the Deer tribe (_Cervidoe_), but generally applied to the entire horns.

APIOCRINIDÆ (Gr. _apion_, a pear; _krinon_, lily). A family of Crinoids--the "Pear-encrinites."

APTERYX (Gr. _a_, without; _pterux_, a wing). A wingless bird of New Zealand, belong to the order _Cursores_.

AQUEOUS (Lat. _aqua_, water). Formed in or by water.

ARACHNIDA (Gr. _arachne_, a spider). A class of the _Articulata_, comprising Spiders, Scorpions, and allied animals.

ARBORESCENT. Branched like a tree.

ARCHÆOCIDARIS (Gr. _archaios_, ancient; Lat. _cidaris_, a diadem). A Palæozoic genus of Sea-urchins, related to the existing _Cidaris_.

ARCHÆOCYATHUS (Gr. _archaios_, ancient; _kuathos_, cup). A genus of Palæozoic fossils allied to the Sponges.

ARCHÆOPTERYX (Gr. _archaios_, ancient; _pterux_, a wing). The singular fossil bird which alone constitutes the order of the _Saururoe_.

ARCTOCYON (Gr. _arctos_, bear; _kuon_, dog). An extinct genus of Carnivora.

ARENACEOUS. Sandy, or composed of grains of sand.

ARENICOLITES (Lat. _arena_, sand; _colo_, I inhabit). A genus founded on burrows supposed to be formed by worms resembling the living Lobworms (_Arenicola_).

ARTICULATA (Lat. _articulus_, a joint). A division of the animal kingdom, comprising Insects, Centipedes, Spiders, and Crustaceans, characterised by the possession of jointed bodies or jointed limbs. The term _Arthropoda_ is now more usually employed.

ARTIODACTYLA (Gr. _artios_, even; _daktulos_, a finger or toe). A division of the hoofed quadrupeds (_Ungulata_) in which each foot has an even number of toes (two or four).

ASAPHUS (Gr. _Asaphes_, obscure). A genus of Trilobites.

ASCOCERAS (Gr. _askos_, a leather bottle; _keras_, horn). A genus of Tetrabranchiate Cephalopods.

ASIPHONATE. Not possessing a respiratory tube or siphon. (Applied to a division of the _Lamellibranchiate_ Molluscs.)

ASTEROID (Gr. _aster_, a star; and _eidos_, form). Star-shaped, or possessing radiating lobes or rays like a star-fish.

ASTEROIDEA. An order of _Echinodermata_, comprising the Star-fishes, characterised by their rayed form.

ASTEROPHYLLITES (Gr. _aster_, a star; _phullon_, leaf). A genus of Palæozoic plants, with leaves in whorls.

ASTRÆIDÆ (Gr. _Astroea_, a proper name). The family of the Star-corals.

ASTYLOSPONGIA (Gr. _a_, without; _stulos_, a column; _spoggos_, a sponge). A genus of Silurian Sponges.

ATHYRIS (Gr. _a_, without; _thura_, door). A genus of Brachiopods.

ATRYPA (Gr. _a_, without; _trupa_, a hole). A genus of Brachiopods.

AVES (Lat. _avis_, a bird). The class of the Birds.

AVICULA (Lat. a little bird). The genus of Bivalve Molluscs comprising the Pearl-oysters.

AXOPHYLLUM (Gr. _axon_, a pivot; _phullon_, a leaf). A genus of Rugose Corals.

AZOIC (Gr. _a_, without; _zoé_, life). Destitute of traces of living beings.

BACULITES (Lat. _baculum_, a staff). A genus of the _Ammonitidoe_.

BALÆNA (Lat. a whale). The genus of the Whalebone Whales.

BALANIDÆ (Gr. _balanos_, an acorn). A family of sessile _Cirripedes_, commonly called "Acorn-shells."

BATRACHIA (Gr. _batrachos_, a frog). Often loosely applied to any of the _Amphibia_, but sometimes restricted to the Amphibians as a class, or to the single order of the _Anoura_.

BELEMNITIDÆ (Gr. _belemnon_, a dart). An extinct group of Dibranchiate Cephalopods, comprising the Belemnites and their allies.

BELEMNOTEUTHIS (Gr. _belemnon_, a dart; _teuthis_, a cuttle-fish). A genus allied to the Belemnites proper.

BELINURUS (Gr. _belos_, a dart; _oura_, tail). A genus of fossil King-crabs.

BELLEROPHON (Gr. proper name). A genus of oceanic Univalves (_Heteropoda_).

BELOTEUTHIS (Gr. _belos_, a dart; _teuthis_, a cuttle-fish). An extinct genus of Dibranchiate Cephalopods.

BEYRICHIA (named after Prof. Beyrich). A genus of Ostracode Crustaceans.

BILATERAL. Having two symmetrical sides.

BIMANA (Lat. _Bis_, twice; _manus_, a hand). The order of _Mammalia_ comprising man alone.

BIPEDAL (Lat. _bis_, twice; _pes_, foot). Walking upon two legs.

BIVALVE (Lat. _bis_, twice; _valvoe_, folding-doors). Composed of two plates or valves; applied to the shell of the _Lamellibranchiata_ and _Brachiopoda_, and to the carapace of certain _Crustacea_.

BLASTOIDEA (Gr. _blastos_, a bud; and _eidos_, form). An extinct order of _Echinodermata_, often called _Pentremites_.

BRACHIOPODA (Gr. _brachion_, an arm; _pous_, the foot). A class or the _Molluscoida_, often called "Lamp-shells," characterised by possessing two fleshy arms continued from the sides of the mouth.

BRACHYURA (Gr. _brachus_, short; _oura_, tail). A tribe of the Decapod _Crustaceans_ with short tails (_i.e._, the Crabs).

BRADYPODIDÆ. (Gr. _bradus_, slow; _podes_, feet). The family of _Edentata_ comprising the Sloths.

BRANCHIA (Gr. _bragchia_, the gill of a fish). A respiratory organ adapted to breathe air dissolved in water.

BRANCHIATE. Possessing gills or branchiæ.

BRONTEUS (Gr. _broné_, thunder--an epithet of Jupiter the Thunderer). A genus of Trilobites.

BRONTOTHERIUM (Gr. _bronté_, thunder; _therion_ beast). An extinct genus of Ungulate Quadrupeds.

BRONTOZOUM (Gr. _bronté_, thunder; _zoön_, animal). A genus founded on the largest footprints of the Triassic Sandstones of Connecticut.

BUCCINUM (Lat. _buccinun_, a trumpet). The genus of Univalves comprising the Whelks.

CAINOZOIC (_See_ Kainozoic.)

CALAMITES (Lat. _calamus_, a reed). Extinct plants with reed-like stems, believed to be gigantic representatives of the _Equisetaceoe_.

CALCAREOUS (Lat. _calx_, lime). Composed of carbonate of lime.

CALICE. The little cup in which the polype of a coralligenous Zoophyte (_Actinozoön_) is contained.

CALYMENE (Gr. _kalumené_, concealed). A genus of Trilobites.

CALYX (Lat. a cup). Applied to the cup-shaped body of a _Crinoid_ (_Echinodermata_).

CAMAROPHORIA (Gr. _kamara_, a chamber; _phero_, I carry). A genus of Brachiopods.

CAMELOPARDALIDÆ. (Lat. _camelus_, a camel; _pardalis_, a panther). The family of the Giraffes.

CANINE (Lat. _canis_, a dog). The eye-tooth of Mammals, or the tooth which is placed at or close to the præmaxillary suture in the upper jaw, and the corresponding tooth in the lower jaw.

CARAPACE. A protective shield. Applied to the upper shell of Crabs, Lobsters, and many other _Crustacea_. Also the upper half of the immovable case in which the body of a Chelonian is protected.

CARCHARODON (Gr. _karcharos_. rough; _odous_, tooth). A genus of Sharks.

CARDIOCARPON (Gr. _kardia_, the heart; _karpos_, fruit). A genus of fossil fruit from the Coal-measures.

CARDIUM (Gr. _kardia_, the heart). The genus of Bivalve Molluscs comprising the Cockles. _Cardinia, Cardiola_, and _Cardita_ have the same derivation.

CARNIVORA (Lat. _caro_, flesh; _voro_, I devour). An order of the _Mammalia_. The "Beasts of Prey."

CARNIVOROUS (Lat. _caro_, flesh; _voro_, I devour). Feeding upon flesh.

CARYOCARIS (Gr. _karua_, a nut; _karis_, a shrimp). A genus of Phyllopod Crustaceans.

CARYOCRINUS (Gr. _karua_, a nut; _krinon_, a lily). A genus of Cystideans.

CAUDAL (Lat. _cauda_, the tail). Belonging to the tail.

CAVICORNIA (Lat. _cavus_, hollow; _cornu_, a horn). The "hollow-horned" Ruminants, in which the horn consists of a central bony "horn-core" surrounded by a horny sheath.

CENTRUM (Gr. _kentron_, the point round which a circle is described by a pair of compasses). The central portion or "body" of a vertebra.

CEPHALASPIDÆ. (Gr. _kephale_, head; _aspis_, shield). A family of fossil fishes.

CEPHALIC (Gr. _kephale_, head). Belonging to the head.

CEPHALOPODA (Gr. _kephale_; and _podes_, feet). A class of the _Mollusca_, comprising the Cuttle-fishes and their allies, in which there is a series of arms ranged round the head.

CERATIOCARIS (Gr. _keras_, a horn; _karis_, a shrimp). A genus of Phyllopod Crustaceans.

CERATITES (Gr. _keras_, a horn). A genus of _Ammonitidoe_.

CERATODUS (Gr. _keras_, a horn; _odous_, tooth). A genus of Dipnoous fishes.

CERVICAL (Lat. _cervix_, the neck). Connected with or belonging to the region of the neck.

CERVIDÆ (Lat. _cervus_, a stag). The family of the Deer.

CESTRAPHORI (Gr. _kestra_, a weapon; _phero_, I carry). The group of the "Cestraciont Fishes," represented at the present day by the Port-Jackson Shark; so called from their defensive spines.

CETACEA (Gr. _ketos_, a whale). The order of Mammals comprising the Whales and the Dolphins.

CETIOSAURUS (Gr. _ketos_, whale; _saura_, lizard). A genus of Deinosaurian Reptiles.

CHEIROPTERA (Gr. _cheir_, hand; _pteron_, wing). The Mammalian order of the Bats.

CHEIROTHERIUM (Gr. _cheir_, hand; _therion_, beast). The generic name applied originally to the hand-shaped footprints of Labyrinthodonts.

CHEIRURUS (Gr. _cheir_, hand; _oura_, tail). A genus of Trilobites.

CHELONIA (Gr. _cheloné_, a tortoise). The Reptilian order of the Tortoises and Turtles.

CHONETES (Gr. _choné_ or _choané_, a chamber or box). A genus of Brachiopods.

CIDARIS (Lat. a diadem). A genus of Sea-urchins.

CLADODUS (Gr. _klados_, branch; _odous_, tooth). A genus of Fishes.

CLATHROPORA (Lat. _clathti_, a trellis; _porus_, a pore). A genus of Lace-corals (_Polyzoa_).

CLISIOPHYLLUM (Gr. _klision_, a hut; _phullon_, leaf). A genus of Rugose Corals.

CLYMENIA (_Clumene_, a proper name). A genus of Tetrabranchiate Cephalopods.

COCCOSTEUS (Gr. _kokkos_, berry; _osteon_, bone). A genus of Ganoid Fishes.

COCHLIODUS (Gr. _kochlion_, a snail-shell; _odous_, tooth). A genus of Cestraciont Fishes.

COELENTERATA (Gr. _koilos_, hollow; _enteron_, the bowel). The sub-kingdom which comprises the _Hydrozoa_ and _Actinozoa_. Proposed by Frey and Leuckhart in place of the old term _Radiata_, which included other animals as well.

COLEOPTERA (Gr. _koleos_, a sheath; _pteron_, wing). The order of Insects (Beetles) in which the anterior pair of wings are hardened, and serve as protective cases for the posterior pair of membranous wings.

COLOSSOCHELYS (Gr. _kolossos_, a gigantic statue; _chelus_, a tortoise). A huge extinct Land-tortoise.

COMATULA (Gr. _koma_, the hair). The Feather-star, so called in allusion to its tress-like arms.

CONDYLE (Gr. _kondulos_, a knuckle). The surface by which one bone articulates with another. Applied especially to the articular surface or surfaces by which the skull articulates with the vertebral column.

CONIFERÆ (Lat. _conus_, a cone; _fero_, I carry). The order of the Firs, Pines, and their allies, in which the fruit is generally a "cone" or "fir-apple."

CONULARIA (Lat. _conulus_, a little-cone). An extinct genus of Pteropods.

COPRALITES (Gr. _kopros_, dung; _lithos_, stone). Properly applied to the fossilised excrements of animals; but often employed to designate phosphatic concretions which are not of this nature.

CORALLITE. The corallum secreted by an _Actinozoön_ which consists of a single polype; or the portion of a composite corallum which belongs to, and is secreted by, an individual polype.

CORALLUM (from the Latin for Red Coral). The hard structures deposited in, or by the tissues of an _Actinozoön_,--commonly called a "coral."

CORIACEOUS (Lat. _corium_. hide). Leathery.

CORYPHODON (Gr. _korus_, helmet; _odous_, tooth). An extinct genus of Mammals, allied to the Tapirs.

CRANIUM (Gr. _kranion_, the skull). The bony or cartilaginous case in which the brain is contained.

CRETACEOUS (Lat. _creta_, chalk). The formation which in Europe contains white chalk as one of its most conspicuous members.

CRINOIDEA (Gr. _krinon_, a lily; _eidos_, form). An order of _Echinodermata_, comprising forms which are usually stalked, and sometimes resemble lilies in shape.

CRIOCERAS (Gr. _krios_, a ram; _keras_, a horn). A genus of _Ammonitidoe_.

CROCODILIA (Gr. _krokodeilos_, a crocodile). An order of Reptiles.

CROSSOPTERYGIDÆ. (Gr. _krossotos_, a fringe; _pterux_, a fin). A sub-order of Ganoids in which the paired fins possess a central lobe.

CRUSTACEA (Lat. _crusta_, a crust). A class of Articulate animals, comprising Crabs, Lobsters, &c., characterised by the possession of a hard shell or crust, which they cast periodically.

CRYPTOGAMS (Gr. _kruptos_, concealed; _gamos_, marriage). A division of plants in which the organs of reproduction are obscure and there are no true flowers.

CTENACANTHUS (Gr. _kteis_, a comb; _akantha_, a thorn). A genus of fossil fishes, named from its fin-spines.

CTENOID (Gr. _kteis_, a comb; _eidos_, form). Applied to those scales of fishes the hinder margins of which are fringed with spines or comb-like projections.

CURSORES (Lat. _curro_, I run). An order of _Aves_, comprising birds destitute of the power of flight, but formed for running vigorously (_e.g._, the Ostrich and Emeu).

CUSPIDATE. Furnished with small pointed eminences or "cusps."

CYATHOCRINUS (Gr. _kuathos_, a cup; _krinon_, a lily). A genus of Crinoids.

CYATHOPHYLLUM (Gr. _kuathos_, a cup; _phullon_, a leaf). A genus of Rugose Corals.

CYCLOID (Gr. _kuklos_, a circle; _eidos_, form). Applied to those scales of fishes which have a regularly circular or elliptical outline with an even margin.

CYCLOPHTHALMUS (Gr. _kuklos_, a circle; _ophthalmos_, eye). A genus of fossil Scorpions.

CYCLOSTOMI (Gr. _kuklos_, and _stoma_, mouth). Sometimes used to designate the Hag-fishes and Lampreys, forming the order _Marsipobranchii_.

CYPRÆA (a name of Venus). The genus of Univalve Molluscs comprising the Cowries.

CYRTOCERAS (Gr. _kurtos_. crooked; _keras_, horn). A genus of Tetrabranchiate Cephalopods.

CYSTIPHYLLUM (Gr. _kustis_, a bladder; _phullon_, a leaf). A genus of Rugose Corals.

CYSTOIDEA (Gr. _kustis_, a bladder; _eidos_, form). The "Globe-crinoids," an extinct order of _Echinodermata_.

DADOXYLON (Gr. _dadion_, a torch; _xulon_, wood). An extinct genus of Coniferous trees.

DECAPODA (Gr. _deka_, ten; _podes_, feet). The division of _Crustacea_ which have ten feet; also the family of Cuttle-fishes, in which there are ten arms or cephalic processes.

DECIDUOUS (Lat. _decido_, I fall off). Applied to parts which fall off or are shed during the life of the animal.

DEINOSAURIA (Gr. _deinos_, terrible; _saura_, lizard). An extinct order of Reptiles.

DEINOTHERIUM (Gr. _deinos_, terrible; _therion_, beast). An extinct genus of Proboscidean Mammals.

DENDROGRAPTUS (Gr. _dendron_, tree; _grapho_, I write). A genus of Graptolites.

DESMIDIÆ. Minute fresh-water plants, of a green colour, without a siliceous epidermis.

DIATOMACEÆ (Gr. _diatemno_, I sever). An order of minute plants which are provided with siliceous envelopes.

DIBRANCHIATA (Gr. _dis_; twice; _bragchia_, gill). The order of _Cephalopoda_ (comprising the Cuttle-fishes, &c.) in which only two gills are present.

DICERAS (Gr. _dis_, twice; _keras_, horn). An extinct genus of Bivalve Molluscs.

DICTYONEMA (Gr. _diktuon_, a net; _nema_, thread). An extinct genus of _Polyzoa_.

DICYNODONTIA (Gr. _dis_, twice; _kuon_, dog; _odous_, tooth). An extinct order of Reptiles.

DIDYMOGRAPTUS (Gr. _didumos_, twin; _grapho_, I write). A genus of Graptolites.

DIMORPHODON (Gr. _dis_, twice; _morphé_, shape; _oduos_, tooth). A genus of Pterosaurian reptiles.

DINICHTHYS (Gr. _deinos_, terrible; _ichthus_, fish). An extinct genus of Fishes.

DINOCERAS (Gr. _deinos_, terrible; _keras_, horn). An extinct genus of Mammals.

DINOPHIS (Gr. _deinos_, terrible; _ophis_, snake). An extinct genus of Snakes.

DINORNIS (Gr. _deinos_, terrible; _ornis_, bird). An extinct genus of Birds.

DIPLOGRAPTUS (Gr. _diplos_, double; _grapho_, I write). A genus of Graptolites.

DIPNOI (Gr. _dis_, twice; _pnoé_, breath). An order of Fishes, comprising the Mud-fishes, so called in allusion to their double mode of respiration.

DIPROTODON (Gr. _dis_, twice; _protos_, first; _odous_, tooth). A genus of extinct Marsupials.

DIPTERA (Gr. _dis_, twice; _pteron_, wing). An order of Insects characterised by the possession of two wings.

DISCOID (Gr. _diskos_, a quoit; _eidos_, form). Shaped like a round plate or quoit.

DOLOMITE (named after M. Dolomieu). Magnesian limestone.

DORSAL (Lat. _dorsum_, the back). Connected with or placed upon the back.

DROMATHERIUM (Gr. _dromaios_, nimble; _therion_, beast). A genus of Triassic Mammals.

DRYOPITHECUS (Gr. _drus_, an oak; _pithekos_, an ape). An extinct genus of Monkeys.

ECHINODERMATA (Gr. _echinos_; and _derma_, skin). A class of animals comprising the Sea-urchins, Star-fishes, and others, most of which have spiny skins.

ECHINOIDEA (Gr. _echinos_; and _eidos_, form). An order of _Echinodermata_, comprising the Sea-urchins.

EDENTATA (Lat. _e_, without; _dens_, tooth). An order of _Mammalia_ often called _Bruta_.

EDENTULOUS. Toothless, without any dental apparatus. Applied to the mouth of any animal, or to the hinge of the Bivalve Molluscs.

ELASMOBRANCHII (Gr. _elasma_, a plate; _bragchia_, gill). An order of Fishes, including the Sharks and Rays.

ENALIOSAURIA (Gr. _enalios_, marine; _saura_, lizard), Sometimes employed as a common term to designate the extinct Reptilian orders of the _Ichthyosauria_ and _Plesiosauria_.

EOCENE (Gr. _eos_, dawn; _kainos_, new or recent). The lowest division of the Tertiary rocks, in which species of existing shells are to a small extent represented.

EOPHYTON (Gr. _eos_, dawn; _phuton_, a plant). A genus of Cambrian fossils, supposed to be of a vegetable nature.

EOZOÖN (Gr. _eos_, dawn; _zoön_, animal). A genus of chambered calcareous organisms found in the Laurentian and Huronian formations.

EQUILATERAL (Lat. _oequus_, equal; _latus_, side). Having its sides equal. Usually applied to the shells of the _Brachiopoda_. When applied to the spiral shells of the _Foraminifera_, it means that all the convolutions of the shell lie in the same plane.

EQUISETACEÆ (Lat. _equus_, horse; _seta_, bristle). A group of Cryptogamous plants, commonly known as "Horse-tails."

EQUIVALVE (Lat. _oequus_, equal; _valvoe_, folding-doors). Applied to shells which are composed of two equal pieces or valves.

ERRANTIA (Lat. _erro_, I wander). An order of _Annelida_, often called _Nereidea_, distinguished by their great locomotive powers.

EUOMPHALUS (Gr. _eu_, well; _omphalos_, navel). An extinct genus of Univalve Molluscs.

EURYPTERIDA (Gr. _eurus_, broad; _pteron_, wing). An extinct sub-order of _Crustacea_.

EXOGYRA (Gr. _exo_, outside; _guros_, circle). An extinct genus of Oysters.

FAUNA (Lat. _Fauni_, the rural deities of the Romans). The general assemblage of the animals of any region or district.

FAVOSITES (Lat. _favus_, a honeycomb). A genus of Tabulate Corals.

FENESTELLIDÆ. (Lat. _fenestella_, a little window). The "Lace-corals," a group of Palæozoic Polyzoans.

FILICES (Lat. _filix_, a fern). The order of Cryptogamic plants comprising the Ferns.

FILIFORM (Lat. _filum_, a thread; _forma_, shape). Thread-shaped.

FLORA (Lat. _Flora_, the goddess of flowers). The general assemblage of the plants of any region or district.

FORAMINIFERA (Lat. _foramen_, an aperture; _fero_, I carry). An order of Protozoa, usually characterised by the possession of a shell perforated by numerous pseudopodial apertures.

FRUGIVOROUS (Lat. _frux_, fruit; _voro_, I devour). Living upon fruits.

FUCOIDS (Lat. _fucus_, sea-weed; Gr. _eidos_, likeness). Fossils, often of an obscure nature, believed to be the remains of sea-weeds.

FUSULINA (Lat. _fusus_, a spindle). An extinct genus of _Foraminifera_.

GANOID (Gr, _ganos_, splendour, brightness). Applied to those scales or plates which are composed of an inferior layer of true bone covered by a superior layer of polished enamel.

GANOIDEI. An order of Fishes.

GASTEROPODA (Gr. _gaster_, stomach; _pous_, foot). The class of the Mollusca comprising the ordinary Univalves, in which locomotion is usually effected by a muscular expansion of the under surface of the body (the "foot").

GLOBIGERINA (Lat. _globus_, a globe; _gero_, I carry). A genus of _Foraminifera_.

GLYPTODON (Gr. _glupho_, I engrave; _odous_, tooth). An extinct genus of Armadillos, so named in allusion to the fluted teeth.

GONIATITES (Gr. _gonia_, angle). A genus of Tetrabranchiate Cephalopods.

GRALLATORES (Lat. _gralloe_, stilts). The order of the long-legged Wading Birds.

GRAPTOLITIDÆ. (Gr. _grapho_, I write; _lithos_, stone). An extinct sub-class of the _Hydrozoa_.

GYMNOSPERMS (Gr. _gumnos_, naked; _sperma_, seed). The Conifers and Cycads, in which the seed is not protected within a seed-vessel.

HALITHERIUM (Gr. _hals_, sea; _therion_, beast). An extinct genus of Sea-cows (_Sirenia_).

HAMITES (Lat. _hamus_, a hook). A genus of the _Ammonitidoe_.

HELIOPHYLLUM (Gr. _helios_, the sun; _phullon_, leaf). A genus of Rugose Corals.

HELLADOTHERIUM (Gr. _Hellas_, Greece; _therion_, beast). An extinct genus of Ungulate Mammals.

HEMIPTERA (Gr. _hemi_, and _pteron_, wing). An order of Insects in which the anterior wings are sometimes "hemelytra."

HESPERORNIS (Gr. _Hesperos_, the evening star; _ornis_, bird). An extinct genus of Birds.

HETEROCERCAL (Gr. _heteros_, diverse; _kerkos_, tail). Applied to the tail of Fishes when it is unsymmetrical, or composed of two unequal lobes.

HETEROPODA (Gr. _heteros_, diverse; _podes_, feet). An aberrant group of the Gasteropods, in which the foot is modified so as to form a swimming organ.

HIPPARION (Gr. _hipparion_, a little horse). An extinct genus of _Equidoe_.

HIPPOPOTAMUS (Gr. _hippos_, horse; _potamos_, river). A genus of Hoofed Quadrupeds--the "River-horses."

HIPPURITIDÆ. (Gr. _hippos_, horse; _oura_, tail). An extinct family of Bivalve Molluscs.

HOLOPTYCHIUS (Gr. _holos_, whole; _ptucé_, wrinkle). An extinct genus of Ganoid Fishes.

HOLOSTOMATA (Gr. _holos_, whole; _stoma_, mouth). A division of _Gasteropodous Molluscs_, in which the aperture of the shell is rounded, or "entire."

HOLOTHUROIDEA (Gr. _holothourion_, and _eidos_, form). An order of _Echinodermata_ comprising the Trepangs.

HOMOCERCAL (Gr. _homos_, same; _kerkol_, tail). Applied to the tail of Fishes when it is symmetrical, or composed of two equal lobes.

HYBODUNTS (Gr. _hubos_, curved; _odous_, tooth). A group of Fishes of which _Hybodus_ is the type-genus.

HYDROIDA (Gr. _hudra_; and _eidos_, form). The sub-class of the _Hydrozoa_, which comprises the animals most nearly allied to the Hydra.

HYDROZOA (Gr. _hudra_; and _zoön_, animal). The class of the _Coelenterata_ which comprises animals constructed after the type of the Hydra.

HYMENOPTERA (Gr. _humen_, a membrane; _pteron_, a wing). An order of Insects (comprising Bees, Ants, &c.) characterised by the possession of four membranous wings.

ICHTHYODORULITE (Gr. _ichthus_, fish; _dorus_, spear; _lithos_, stone). The fossil fin-spine of Fishes.

ICHTHYOPTERYGIA (Gr. _ichthus_; _pterux_, wing). An extinct order of Reptiles.

ICHTHYORNIS (Gr. _ichthus_, fish; _ornis_, bird). An extinct genus of Birds.

ICHTHYOSAURIA (Gr. _ichthus_; _saura_, lizard). Synonymous with _Ichthyopterygia_.

IGUANODON (_Iguana_, a living lizard; Gr. _odous_, tooth). A genus of Deinosaurian Reptiles.

INCISOR (Lat. _incido_, I cut). The cutting teeth fixed in the intermaxillary bones of the _Mammalia_, and the corresponding teeth in the lower jaw.

INEQUILATERAL. Having the two sides unequal, as in the case of the shells of the ordinary bivalves (_Lamellibranchiata_). When applied to the shells of the _Foraminifera_, it implies that the convolutions of the shell do not lie in the same plane, but are obliquely wound round an axis.

INEQUIVALVE. Composed of two unequal pieces or valves.

INOCERAMUS (Gr. _is_, a fibre; _keramos_, an earthen vessel). An extinct genus of Bivalve Molluscs.

INSECTA (Lat. _inseco_, I cut into). The class of articulate animals commonly known as Insects.

INSECTIVORA (Lat. _insectum_, an insect; _voro_, I devour). An order of Mammals.

INSECTIVOROUS. Living upon Insects.

INSESSORES (Lat. _insedeo_, I sit upon). The order of the Perching Birds, often called _Passeres_.

INTERAMBULACRA. The rows of plates in an _Echinoid_ which are not perforated for the emission of the "tube-feet."

INTERMMAXILLÆ or PRÆMAXILLÆ. The two bones which are situated between the two superior maxillæ in _Vertebrata_. In man, and some monkeys, the præmaxillæ anchylose with the maxillæ, so as to be irrecognisable in the adult.

INVERTEBRATA (Lat. _in_, without; _vertebra_, a bone of the back). Animals without a spinal column or backbone.

ISOPODA. (Gr. _isos_, equal; _podes_, feet). An order of _Crustacea_ in which the feet are like one another and equal.

KAINOZOIC (Gr. _kainos_, recent; _zoe_, life). The Tertiary period in Geology comprising those formations in which the organic remains approximate more or less closely to the existing fauna and flora.

LABYRINTHODONTIA (Gr. _laburinthos_, a labyrinth; _odous_, tooth). An extinct order of _Amphibia_, so called from the complex microscopic structure of the teeth.

LACERTILIA (Lat. _lacerta_, a lizard). An order of _Reptilia_ comprising the Lizards and Slow-worms.

LAMELLIBRANCHIATA (Lat. _lamella_, a plate; Gr. _bragchia_, gill). The class of _Mollusca_ comprising the ordinary bivalves, characterised by the possession of lamellar gills.

LEPIDODENDRON (Gr. _lepis_, a scale; _dendron_, a tree). A genus of extinct plants, so named from the scale-like scars upon the stem left by the falling off of the leaves.

LEPIDOPTERA (Gr. _lepis_, a scale; _pteron_, a wing). An order of Insects, comprising Butterflies and Moths, characterised by possessing four wings which are usually covered with minute scales.

LEPIDOSIREN (Gr. _lepis_, a scale; _seiren_, a siren--the generic name of the Mud-eel or _Siren lacertina_). A genus of Dipnoous fishes, comprising the "Mud-fishes."

LEPIDOSTROBUS (Gr. _lepis_, a scale; _strobilos_, a fir-cone). A genus founded on the cones of _Lepidodendron_.

LEPTÆNA (Gr. _leptos_. slender). A genus of Brachiopods.

LINGULA (Lat. _lingula_, a little tongue). A genus of Brachiopods.

LYCOPODIACEÆ (Gr. _lupos_, a wolf; _pous_, foot). The group of Cryptogamic plants generally known as "Club-mosses."

MACHÆRACANTHUS (Gr. _machaira_, a sabre; _acantha_, thorn or spine). An extinct genus of Fishes.

MACHAIRODUS (Gr. _machaira_, a sabre; _odous_, tooth). An extinct genus of Carnivora.

MACROTHERIUM (Gr. _makros_, long; _therion_. beast). An extinct genus of Edentata.

MACRURA (Gr. _makros_, long; _oura_, tail). A tribe of Decapod _Crustaceans_ with long tails (e.g., the Lobster, Shrimp, &c.)

MAMMALIA (Lat. _mamma_, the breast). The class of Vertebrate animals which suckle their young.

MANDIBLE (Lat. _mandibulum_, a jaw). The upper pair of jaws in Insects; also applied to one of the pairs of jaws in _Crustacea_ and Spiders, to the beak of Cephalopods, the lower jaw of Vertebrates, &c.

MANTLE. The external integument of most of the Mollusca, which is largely developed, and forms a cloak in which the viscera are protected. Technically called the "pallium."

MANUS (Lat. the hand). The hand of the higher Vertebrates.

MARSIPOBRANCHII (Gr. _marsipos_, a pouch; _bragchia_, gill). The order of Fishes comprising the Hag-fishes and Lampreys, with pouch-like gills.

MARSUPIALIA (Lat. _marsupium_, a pouch). An order of Mammals in which the females mostly have an abdominal pouch in which the young are carried.

MASTODON (Gr. _mastos_, nipple; _odous_, tooth). An extinct genus of Elephantine Mammals.

MEGALONYX (Gr. _megas_, great; _onux_, nail). An extinct genus of Edentate Mammals.

MEGALOSAURUS (Gr. _megas_, great; _saura_, lizard). A genus of Deinosaurian Reptiles.

MEGATHERIUM (Gr. _megas_, great; _therion_, beast). An extinct genus of Edentata.

MESOZOIC (Gr. _mesos_, middle; and _zoe_, life). The Secondary period in Geology.

MICROLESTES (Gr. _mikros_, little; _lestes_, thief). An extinct genus of Triassic Mammals.

MILLEPORA (Lat. _mille_, one thousand; _porus_, a pore). A genus of "Tabulate Corals."

MIOCENE (Gr. _meion_, less; _kainol_, new). The Middle Tertiary period.

MOLARS (Lat. _mola_, a mill). The "grinders" in man, or the teeth in diphyodont Mammals which are not preceded by milk-teeth.

MOLLUSCA (Lat. _mollis_, soft). The sub-kingdom which includes the Shell-fish proper, the _Polyzoa_, the _Tunicata_, and the Lamp-shells; so called from the generally soft nature of their bodies.

MOLLUSCOIDA (_Mollusca_; Gr. _eidos_, form). The lower division of the _Mollusca_, comprising the _Polyzoa, Tunicata_, and _Brachiopoda_.

MONOGRAPTUS (Gr. _monos_, single; _grapho_, I write). A genus of Graptolites.

MYLODON (Gr. _mulos_, a mill; _odous_, tooth). An extinct genus of Edentate Mammals.

MYRIAPODA or MYRIOPODA (Gr. _murios_, ten thousand; _podes_, feet). A class of _Arthropoda_ comprising the Centipedes and their allies, characterised by their numerous feet.

NATATORES (Lat. _nare_, to swim). The order of the Swimming Birds.

NATATORY (Lat. _nare_, to swim). Formed for swimming.

NAUTILOID. Resembling the shell of the _Nautilus_ in shape.

NERVURES (Lat. _nervus_, a sinew). The ribs which support the membranous wings of insects.

NEUROPTERA (Gr. _neuron_, a nerve; _pteron_, a wing). An order of Insects characterised by four membranous wings with numerous reticulated nervures (_e.g._, Dragon-flies).

NEUROPTERIS (Gr. _neuron_, a nerve; _pteris_, a fern). An extinct genus of Ferns.

NOTHOSAURUS (Gr. _nothos_, spurious; _saura_, lizard). A genus of _Plesiosaurian_ Reptiles.

NOTOCHORD (Gr. _notos_, back; _chorde_, string). A cellular rod which is developed in the embryo of Vertebrates immediately beneath the spinal cord, and which is usually replaced in the adult by the vertebral column. Often it is spoken of as the "chorda dorsalis."

NUDIBRANCHIATA (Lat. _nudus_, naked; and Gr. _bragchia_, gill). An order of the _Gasteropoda_ in which the gills are naked.

NUMMULINA (Lat. _nummus_, a coin). A genus of _Foraminifera_, comprising the coin-shaped "Nummulites."

OBOLELLA (Lat. dim. of _obolus_, a small coin). An extinct genus of Brachiopods.

OCCIPITAL. Connected with the _occiput_, or the back part of the head.

OCEANIC. Applied to animals which inhabit the open ocean (= pelagic).

ODONTOPTERYX (Gr. _oduos_, tooth; _pterux_, wing). An extinct genus of Birds.

ODONTORNITHES (Gr. _oduos_, tooth; _ornis_, bird). The extinct order of Birds, comprising forms with distinct teeth in sockets.

OLIGOCENE (Gr. _oligos_, few; _kainos_, new). A name used by many Continental geologists as synonymous with the Lower Miocene.

OPHIDIA (Gr. _ophis_, a serpent). The order of Reptiles comprising the Snakes.

OPHIUROIDEA (Gr. _ophis_, snake; _oura_, tail; _eidos_, form). An order of _Echinodermata_, comprising the Brittle-stars and Sand-stars.

ORNITHOSCELIDA (Gr. _ornis_, bird; _skelos_, leg). Applied by Huxley to the Deinosaurian Reptiles, together with the genus _Compsognathus_, on account of the bird-like character of their hind-limbs.

ORTHIS (Gr. _orthos_, straight). A genus of Brachiopods, named in allusion to the straight hinge-line.

ORTHOCERATIDÆ (Gr. _orthos_, straight; _keras_, horn). A family of the _Nautilidoe_, in which the shell is straight, or nearly so.

ORTHOPTERA (Gr. _orthos_, straight; _pteron_, wing). An order of Insects.

OSTEOLEPIS (Gr. _osteon_, bone; _lepis_, scale). An extinct genus of Ganoid Fishes.

OSTRACODA (Gr. _ostrakon_, a shell). An order of small Crustaceans which are enclosed in bivalve shells.

OTODUS (Gr. _ota_, ears; _odous_, tooth). An extinct genus of Sharks.

OUDENODON (Gr. _ouden_, none; _odous_, tooth). A genus of Dicynodont Reptiles.

OVIBUS (Lat. _ovis_, sheep; _bos_, ox). The genus comprising the Musk-ox.

PACHYDERMATA (Gr. _pachus_, thick; _derma_, skin). An old Mammalian order constituted by Cuvier for the reception of the Rhinoceros, Hippopotamus, Elephant, &c.

PALÆASTER (Gr. _palaios_, ancient; _aster_, star). An extinct genus of Star-fishes.

PALÆOCARIS (Gr. _palaios_, ancient; _karis_, shrimp). An extinct genus of Decapod Crustaceans.

PALÆOLITHIC (Gr. _palaios_, ancient; _lithos_, stone). Applied to the rude stone implements of the earliest known races of men, to the men who made these implements, or to the period at which they were made.

PALÆONTOLOGY (Gr. _palaios_, ancient; and _logos_, discourse). The science of fossil remains or of extinct organised beings.

PALÆOPHIS (Gr. _palaios_, ancient; _ophis_, serpent). An extinct genus of Snakes.

PALÆOSAURUS (Gr. _palaios_, ancient; _saura_, lizard). A genus of Thecodont Reptiles.

PALÆOTHERIDÆ. (Gr. _palaios_, ancient; _ther_, beast). A group of Tertiary Ungulates.

PALÆOZOIC (Gr. _palaios_, ancient; and _zoe_, life). Applied to the oldest of the great geological epochs.

PARADOXIDES (Lat. _paradoxus_, marvellous). A genus of Trilobites.

PATAGIUM (Lat. the border of a dress). Applied to the expansion of the integument by which Bats, Flying Squirrels, and other animals support themselves in the air.

PECOPTERIS (Gr. _peko_, I comb; _pteris_, a fern). An extinct genus of Ferns.

PECTEN (Lat. a comb). The genus of Bivalve Molluscs comprising the Scallops.

PECTORAL (Lat. _pectus_, chest). Connected with, or placed upon, the chest.

PENTACRINUS (Gr. _penta_, five; _krinon_, lily). A genus of Crinoids in which the column is five-sided.

PENTAMERUS (Gr. _penta_, five; _meros_, part). An extinct genus of Brachiopods.

PENTREMITES (Gr. _penta_, five; _trema_, aperture). A genus of _Blastoidea_, so named in allusion to the apertures at the summit of the calyx.

PERENNIBRANCHIATA (Lat. _perennis_, perpetual; Gr. _bragchia_, gill). Applied to those Amphibia in which the gills are permanently retained throughout life.

PERISSODACTYLA (Gr. _perissos_, uneven; _daktulos_, finger). Applied to those Hoofed Quadrupeds (_Ungulata_) in which the feet have an uneven number of toes.

PETALOID. Shaped like the petal of a flower.

PHACOPS (Gr. _phaké_, a lentil; _ops_, the eye). A genus of Trilobites.

PHALANGES (Gr. _phalanx_, a row). The small bones composing the digits of the higher _Vertebrata_. Normally each digit has three phalanges.

PHANEROGAMS (Gr. _phaneros_, visible; _gamos_, marriage). Plants which have the organs of reproduction conspicuous, and which bear true flowers.

PHARYNGOBRANCHII (Gr. _pharugx_, pharynx; _bragchia_, gill). The order of Fishes comprising only the Lancelet.

PHASCOLOTHERIUM (Gr. _phaskolos_, a pouch; _therion_, a beast). A genus of Oolitic Mammals.

PHRAGMACONE (Gr. _phragma_, a partition; and _konos_, a cone). The chambered portion of the internal shell of a _Belemnite_.

PHYLLOPODA (Gr. _phullon_, leaf; and _pous_, foot). An order of _Crustacea_.

PINNATE (Lat. _pinna_, a feather). Feather-shaped; or possessing lateral processes.

PINNIGRADA (Lat. _pinna_, a feather; _gradior_, I walk). The group of _Carnivora_, comprising the Seals and Walruses, adapted for an aquatic life. Often called _Pinnipedia_.

PINNULÆ. (Lat. dim. of _pinna_). The lateral processes of the arms of _Crinoids_.

PISCES (Lat. _piscis_, a fish). The class of Vertebrates comprising the Fishes.

PLACOID (Gr. _plax_, a plate; _eidos_, form). Applied to the irregular bony plates, grains, or spines which are found in the skin of various fishes (_Elasmobranchii_).

PLAGIOSTOMI (Gr. _plagios_, transverse; _stoma_, mouth). The Sharks and Rays, in which the mouth is transverse, and is placed on the under surface of the head.

PLATYCERAS (Gr. _platus_, broad; _keras_, horn). A genus of Univalve Molluscs.

PLATYCRINUS (Gr. _platus_, broad; _krinom_, lily). A genus of Crinoidea.

PLATYRHINA (Gr. _platus_, broad; _rhines_, nostrils). A group of the _Quadrumana_.

PLATYSOMUS (Gr. _platus_, wide; _soma_, body). A genus of Ganoid Fishes.

PLEISTOCENE (Gr. _pleistos_, most; _kainos_, new). Often used as synonymous with "Post-Pliocene."

PLEUROTOMARIA (Gr. _pleura_, the side; _tomé_, notch). A genus of Univalve shells.

PLIOCENE (Gr. _pleion_, more; _kainos_, new). The later Tertiary period.

PLIOPITHECUS (Gr. _pleion_, more; _pithekos_, ape). An extinct genus of monkeys.

PLIOSAURUS (Gr. _pleion_, more; _saura_, lizard). A genus of Plesiosaurian Reptiles.

POLYCYSTINA (Gr. _polus_, many; and _kustis_, a cyst). An order of _Protozoa_ with foraminated siliceous shells.

POLYPARY. The hard chitinous covering secreted by many of the _Hydrozoa_.

POLYPE (Gr. _polus_, many; _pous_, foot). Restricted to the single individual of a simple _Actinozoön_, such as a Sea-anemone, or to the separate zooids of a compound _Actinozoön_. Often applied indiscriminately to any of the _Coelenterata_, or even to the Polyzoa.

POLYPORA (Gr. _polus_, many; _poros_, a passage). A genus of Lace-corals (_Fenestellidoe_).

POLYTHALAMOUS (Gr. _polus_; and _thalamos_, chamber). Having many chambers; applied to the shells of _Foraminifera_ and _Cephalopoda_.

POLYZOA (Gr. _polus_; and _zoön_, animal). A division of the _Molluscoida_ comprising compound animals, such as the Sea-mat--sometimes called _Bryozoa_.

PORIFERA (Lat. _porus_, pore; and _fero_, I carry). Sometimes used to designate the _Foraminifera_, or the _Sponges_.

PRÆMOLARS (Lat. _proe_, before; _molares_, the grinders). The molar teeth of Mammals which succeed the molars of the milk-set of teeth. In man, the bicuspid teeth.

PROBOSCIDEA (Lat. _proboscis_, the snout). The order of Mammals comprising the Elephants.

PROCOELOUS (Gr. _pro_, before; _koilos_, hollow). Applied to vertebræ the bodies of which are hollow or concave in front.

PRODUCTA (Lat. _productus_, drawn out or extended). An extinct genus of Brachiopods, in which the shell is "eared," or has its lateral angles drawn out.

PROTICHNITES (Gr. _protos_, first; _ichnos_, footprint). Applied to certain impressions in the Potsdam sandstone of North America, believed to have been produced by large Crustaceans.

PROTOPHYTA (Gr. _protos_; and _phuton_, plant). The lowest division of plants.

PROTOPLASM (Gr. _protos_; and _plasso_ I mould). The elementary basis of organised tissues. Sometimes used synonymously for the "sarcode" of the _Protozoa_.

PROTOROSAURUS or PROTEROSAURUS (Gr. _protos_, first; _orao_, I see or discover; _saura_, lizard: or _proteros_, earlier; _saura_, lizard). A genus of Permian lizards.

PROTOZOA (Gr. _protos_; and _zoön_, animal). The lowest division of the animal kingdom.

PSAMMODUS (Gr. _psammos_, sand; _odous_, tooth). An extinct genus of Cestraciont Sharks.

PSEUDOPODIA (Gr. _pseudos_, falsity; and _pous_, foot). The extensions of the body-substance which are put forth by the _Rhizopoda_ at will, and which serve for locomotion and prehension.

PSILOPHYTON (Gr. _psilos_, bare; _phuton_, plant). An extinct genus of Lycopodiaceous plants.

PTERANODON (Gr. _pteron_, wing; _a_, without; _odous_, tooth). A genus of Pterosaurian Reptiles.

PTERASPIS (Gr. _pteron_, wing; _aspis_, shield). A genus of Ganoid Fishes.

PTERICHTHYS (Gr. _pteron_, wing; _ichthus_, fish). A genus of Ganoid Fishes.

PTERODACTYLUS (Gr. _pteron_, wing; _daktulos_, finger). A genus of Pterosaurian Reptiles.

PTEROPODA (Gr. _pteron_, wing; and _pous_, foot). A class of the _Mollusca_ which swim by means of fins attached near the head.

PTEROSAURIA (Gr. _pteron_, wing; _saura_, lizard). An extinct order of Reptiles.

PTILODICTYA (Gr. _ptilon_, a feather; _diktuon_, a net). An extinct genus of _Polyzoa_.

PTYCHOCERAS (Gr. _ptucé_, a fold; _keras_, a horn). A genus of _Ammonitidoe_.

PULMONATE. Possessing lungs.

PYRIFORM (Lat. _pyrus_, a pear; and _forma_, form). Pear-shaped.

QUADRUMANA (Lat. _quatuor_, four; _manus_, hand). The order of Mammals comprising the Apes, Monkeys, Baboons, Lemurs, &c.

RADIATA (Lat. _radius_, a ray). Formerly applied to a large number of animals which are now placed in separate sub-kingdoms (e.g., the _Coelenterata_, the _Echinodermata_, the _Infusoria_, &c.)

RADIOLARIA (Lat. _radius_, a ray). A division of _Protozoa_.

RAMUS (Lat. a branch). Applied to each half or branch of the lower jaw, or mandible, of Vertebrates.

RAPTORES (Lat. _rapto_, I plunder). The order of the Birds of Prey.

RASORES (Lat. _rado_, I scratch). The order of the Scratching Birds (Fowls. Pigeons, &c.)

RECEPTACULITES (Lat. _receptaculum_, a storehouse). An extinct genus of Protozoa.

REPTILIA (Lat. _repto_, I crawl). The class of the _Vertebrata_ comprising the Tortoises, Snakes, Lizards, Crocodiles, &c.

RETEPORA (Lat. _reté_, a net; _porus_, a pore). A genus of Lace-corals (_Polyzoa_).

RHAMPHORHYNCHUS (Gr. _rhamphos_, beak; _rhugchos_, nose). A genus of Pterosaurian Reptiles.

RHINOCEROS (Gr. _rhis_, the nose; _keras_, horn). A genus of Hoofed Quadrupeds.

RHIZOPODA (Gr. _rhiza_, a root; and _pous_, foot). The division of _Protozoa_ comprising all those which are capable of emitting pseudopodia.

RHYNCHOLITES (Gr. _rhugchos_, beak; and _lithos_, stone). Beak-shaped fossils consisting of the mandibles of _Cephalopoda_.

RHYNCHONELLA (Gr. _rhugchos_, nose or beak). A genus of Brachiopods.

RODENTIA (Lat. _rodo_, I gnaw). An order of the Mammals; often called _Glires_ (Lat. _glis_, a dormouse).

ROTALIA (Lat. _rota_, a wheel). A genus of _Foraminifera_.

RUGOSA (Lat. _rugosus_, wrinkled). An order of Corals.

RUMINANTIA (Lat. _ruminor_, I chew the cud). The group of Hoofed Quadrupeds (_Ungulata_) which "ruminate" or chew the cud.

SARCODE (Gr. _sarx_, flesh; _eidos_, form). The jelly-like substance of which the bodies of the _Protozoa_ are composed. It is an albuminous body containing oil-granules, and is sometimes called "animal protoplasm."

SAURIA (Gr. _saura_, a lizard). Any lizard-like Reptile is often spoken of as a "Saurian;" but the term is sometimes restricted to the Crocodiles alone, or to the Crocodiles and Lacertilians.

SAUROPTERYGIA (Gr. _sauro_; _pterux_, wing). An extinct order of Reptiles, called by Huxley _Plesiosauria_, from the typical genus _Plesiosaurus_.

SAURURÆ (Gr. _saura_; _oura_, tail). The extinct order of Birds comprising only the _Archoeopteryx_.

SCANSORES (Lat. _scando_, I climb). The order of the Climbing Birds (Parrots, Woodpeckers, &c.)

SCAPHITES (Lat. _scapha_, a boat). A genus of the _Ammonitidoe_.

SCOLITHUS (Gr. _skolex_, a worm; _lithos_, a stone). The vertical burrows of sea-worms in rocks.

SCUTA (Lat. _scutum_, a shield). Applied to any shield-like plates; especially to those which are developed in the integument of many Reptiles.

SELACHIA or SELACHII (Gr. _selachos_, a cartilaginous fish, probably a shark). The sub-order of _Elasmobranchii_ comprising the Sharks and Dog-fishes.

SEPIOSTAIRE. The internal shell of the Sepia, commonly known as the "cuttle-bone."

SEPTA. Partitions.

SERPENTIFORM. Resembling a serpent in shape.

SERTULARIDA (Lat. _sertum_, a wreath). An order of _Hydrozoa_.

SESSILE (Lat. _sedo_, I sit). Not supported upon a stalk or peduncle; attached by a base.

SETHÆ (Lat. bristles). Bristles or long stiff hairs.

SIGILLARIOIDS (Lat. _sigilla_, little images). A group of extinct plants of which _Sigillaria_ is the type, so called from the seal-like markings on the bark.

SILICEOUS (Lat. _silex_, flint). Composed of flint.

SINISTRAL (Lat. _sinistra_, the left hand). Left-handed; applied to the direction of the spiral in certain shells, which are said to be "reversed."

SIPHON (Gr. a tube). Applied to the respiratory tubes in the _Mollusca_; also to other tubes of different functions.

SIPHONIA (Gr. _siphon_, a tube). A genus of fossil Sponges.

SIPHONOSTOMATA (Gr. _siphon_; and _stoma_, mouth). The division of _Gasteropodous Molluscs_ in which the aperture of the shell is not "entire," but possesses a notch or tube for the emission of the respiratory siphon.

SIPHUNCLE (Lat. _siphunculus_, a little tube). The tube which connects together the various chambers of the shell of certain _Cephalopoda_ (_e.g._, the Pearly Nautilus).

SIRENIA (Gr. _seiren_. a mermaid). The order of _Mammalia_ comprising the Dugongs and Manatees.

SIVATHERIUM (_Siva_, a Hindoo deity; Gr. _therion_, beast). An extinct genus of Hoofed Quadrupeds.

SOLIDUNGULA (Lat. _solidus_, solid; _ungula_, a hoof). The group of Hoofed Quadrupeds comprising the Horse, Ass, and Zebra, in which each foot has only a single solid hoof. Often called _Solipedia_.

SPHENOPTERIS (Gr. _sphen_, a wedge; _pteris_, a fern). An extinct genus of ferns.

SPICULA (Lat. _spicidum_, a point). Pointed needle-shaped bodies.

SPIRIFERA (Lat. _spira_, a spire or coil; _fero_, I carry). An extinct genus of Brachiopods, with large spiral supports for the "arms."

SPIRORBIS (Lat. _spira_, a spire; _orbis_, a circle). A genus of tube-inhabiting Annelides, in which the shelly tube is coiled into a spiral disc.

SPONGIDA (Gr. _spoggos_, a sponge). The division of _Protozoa_ commonly known as sponges.

STALACTITES (Gr. _stalasso_, I drop). Icicle-like encrustations and deposits of lime, which hang from the roof of caverns in limestone.

STALAGMITE (Gr. _stalagma_, a drop). Encrustations of lime formed on the floor of caverns which are hollowed out of limestone.

STIGMARIA (Gr. _stigma_, a mark made with a pointed instrument). A genus founded on the roots of various species of _Sigillaria_.

STRATUM (Lat. _stratus_, spread out; or _stratum_, a thing spread out). A layer of rock.

STROMATOPORA (Gr. _stroma_, a thing spread out; _paras_, a passage or pore). A Palæozoic genus of _Protozoa_.

STROPHOHENA (Gr. _strophao_, I twist; _mené_, moon). An extinct genus of Brachiopods.

SUB-CALCAREOUS. Somewhat calcareous.

SUB-CENTRAL. Nearly central, but not quite.

SUTURE (Lat. _suo_, I sew). The line of junction of two parts which are immovably connected together. Applied to the line where the whorls of a univalve shell join one another; also to the lines made upon the exterior of the shell of a chambered _Cephalopod_ by the margins of the septa.

SYRINGOPORA (Gr. _surigx_, a pipe; _poros_, a pore). A genus of Tabulate Corals.

TABULÆ. (Lat. _tabula_, a tablet). Horizontal plates or floors found in some Corals, extending across the cavity of the "theca" from side to side.

TEGUMENTARY (Lat. _tegumentum_, a covering). Connected with the integument or skin.

TELEOSAURUS (Gr. _teleios_, perfect; _saura_, lizard). An extinct genus of Crocodilian Reptiles.

TELEOSTEI (Gr. _teleios_, perfect; _osteon_, bone). The order of the "Bony Fishes."

TELSON (Gr. a limit). The last joint in the abdomen of _Crustacea_; variously regarded as a segment without appendages, or as an azygous appendage.

TENTACULITES (Lat. _tentaculum_, a feeler). A genus of _Pteropoda_.

TEREBRATULA (Lat. _terebratus_, bored or pierced). A genus of _Brachiopoda_, so called in allusion to the perforated beak of the ventral valve.

TEST (Lat. _testa_, shell). The shell of _Mollusca_, which are for this reason sometimes called "_Testacea_;" also, the calcareous case of _Echinoderms_; also, the thick leathery outer tunic in the _Tunicata_.

TESTACEOUS. Provided with a shell or hard covering.

TESTUDINIDÆ (Lat. _testudo_, a tortoise). The family of the Tortoises.

TETRABRANCHIATA (Gr. _tetra_, four; _bragchia_, gill). The order of _Cephalopoda_ characterised by the possession of four gills.

TEXTULARIA. (Lat. _textilis_, woven). A genus of _Foraminifera_.

THECA (Gr. _theké_, a sheath). A genus of Pteropods.

THECODONTOSAURUS (Gr. _theké_, a sheath; _odous_, tooth; _saura_, lizard). A genus of "Thecodont" Reptiles, so named in allusion to the fact that the teeth are sunk in distinct sockets.

THERIODONT (Gr. _therion_, a beast; _odous_, tooth). A group of Reptiles so named by Owen in allusion to the Mammalian character of their teeth.

THORAX (Gr. a breastplate). The region of the chest.

THYLACOLEO (Gr. _thulakos_, a pouch; _leo_, a lion). An extinct genus of Marsupials.

TRIGONIA (Gr. _treis_, three; _gonia_, angle). A genus of Bivalve Molluscs.

TRIGONOCARPON (Gr. _treis_, three; _gonia_. angle; _karpos_, fruit). A genus founded on fossil fruits of a three-angled form.

TRILOBITA (Gr. _treis_, three; _lobos_, a lobe). An extinct order of _Crustaceans_.

TRINUCLEUS (Lat. _tris_, three; _nucleus_, a kernel). A genus of Trilobites.

TROGONTHERIUM (Gr. _trogo_, I gnaw; _therion_, beast). An extinct genus of Beavers.

TUBICOLA (Lat. _tuba_, a tube; and _colo_, I inhabit). The order of _Annelida_ which construct a tubular case in which they protect themselves.

TUBICOLOUS. Inhabiting a tube.

TUNICATA (Lat. _tunica_, a cloak). A class of _Molluscoida_ which are enveloped in a tough leathery case or "test."

TURBINATED (Lat. _turbo_, a top). Top-shaped; conical with a round base.

TURRILITES (Lat, _turris_, a tower). A genus of the _Ammonitidoe_.

UMBO (Lat. the boss of a shield). The beak of a bivalve shell.

UNGUICULATE (Lat. _unguis_, nail). Furnished with claws.

UNGULATA (Lat. _ungula_, hoof). The order of Mammals comprising the Hoofed Quadrupeds.

UNGULATE. Furnished with expanded nails constituting hoofs.

UNILOCULAR (Lat. _unus_, one; and _loculus_. a little purse). Possessing a single cavity or chamber. Applied to the shells of _Foraminifera_ and _Mollusca_.

UNIVALVE (Lat. _unus_, one; _valvoe_, folding-doors). A shell composed of a single piece or valve.

URODELA (Gr. _oura_, tail; _delos_, visible). The order of the Tailed Amphibians (Newts, &c.)

VENTRAL (Lat. _venter_, the stomach). Relating to the inferior surface of the body.

VENTRICULITES (Lat. _ventriculum_, a little stomach). A genus of siliceous Sponges.

VERMIFORM (Lat. _vermis_, worm; and _forma_, form). Worm-like.

VERTEBRA (Lat. _verto_, I turn). One of the bony segments of the vertebral column or backbone.

VERTEBRATA (Lat. _vertebra_, a bone of the back, from _vertere_, to turn). The division of the Animal Kingdom roughly characterised by the possession of a backbone.

VESICLE (Lat. _vesica_, a bladder). A little sac or cyst.

WHORL. The spiral turn of a univalve shell.

XIPHOSURA (Gr. _xiphos_, a sworn; and _oura_, tail). An order of _Crustacea_, comprising the _Limuli_ or King-Crabs, characterised by their long sword-like tails.

XYLOBIUS (Gr. _xulon_, wood; _bios_, life). An extinct genus of Myriapods, named in allusion to the fact that the animal lived on decaying wood.

ZAPHRENTIS (proper name). A genus of Rugose Corals.

ZEUGLODONTIDÆ. (Gr. _zeuglé_, a yoke; _odous_, a tooth). An extinct family of Cetaceans, in which the molar teeth are two-fanged, and look as if composed of two parts united by a neck.

ZOOPHYTE (Gr. _zoön_, animal; _phuton_, plant). Loosely applied to many plant-like animals, such as Sponges, Corals, Sea-anemones, Sea-mats, &c.

INDEX.

Acadian Group. _Acer_. _Acervularia_. _Acidaspis_. Acorn-shells. _Acroculia_. _Acrodus; nobilis_. _Acrotreta_. _Acroura_. _Actinocrinus_. _Æglina_. _Æpiornis_. _Agnostus; rex_. _Alces malchis_. _Alecto_. _Alethopteris_. _Algoe_ (_see_ Sea-weeds). Alligators. _Alnus_. _Amblypterus; macropterus_. _Ambonychia_. _Ammonites; Humpresianus; bifrons_. _Ammonitidoe_. _Amphibia_; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Miocene. _Amphicyon_. _Amphilestes_. _Amphispongia_. _Amphistegina_. _Amphitherium; Prevostii_. _Amphitragulus_. _Amplexus; coralloides_. _Ampyx_. _Anachytes_. _Anchitherium_. _Ancyloceras; Matheronianus_. _Ancylotherium Pentelici_. _Andrias Scheuchzeri_. _Angiosperms_. Animal Kingdom, divisions of. _Anisopus_. _Annelida_, of the Cambrian period; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous. _Annularia_. _Anomodontia_. _Anoplotheridoe_. _Anoplotherium; commune_. Ant-eaters. Antelopes. _Anthracosaurus Russelli_. _Anthrapaloemon gracilis_. _Antilocapra_. _Antilope quadricornis_. Antwerp Crag. Apes. _Apiocrinus_. _Apteryx_. Aqueous rocks. _Arachnida_ of the Coal-measures. Aralo-Caspian Beds. _Araucaria_. _Araucarioxylon_. _Arca; antiqua_. _Archoeocidaris_. _Archoeocyathus_. _Archoeopteryx; macrura_. _Archoeospoerinoe_. _Archimedes; Wortheni_. _Archiulus_. Arctic regions, Miocene flora of. _Arctocyon_. Arenaceous rocks. _Arenicolites; didymus_. Arenig rocks. Argillaceous rocks. Armadillos. _Artiodactyle Ungulates_. _Asaphus; tyrannus_. _Ascoceras_. _Aspidella_. _Aspidura loricata_. _Astarte borealis_. _Asterophyllites_. _Asterosteus_. _Astroeidoe_. _Astroeospongia_. _Astylospongia; proemorsa_. _Athyris; subtilita_. Atlantic Ooze. _Atrypa; congesta; hemispoerica; reticularis_. Auger-shells. Aurochs. Aves (_see_ Birds). _Avicula; cantorta; socialis_. "Avicula contorta Beds". _Aviculidoe_. _Aviculopecten_. _Axophyllum_. Aymestry Limestone. Azoic rocks.

_Baculites; anceps_. Bagshot and Bracklesham Beds. _Bakewellia_. _Baloena_. Bala Group. Bala Limestone. _Balanidoe_. _Banksia_. Barbadoes Earth. Barnacles. Bath Oolite. Bats. Bears. Beaver. Beetles. _Belemnitella mucronata_. _Beleminites; canaliculatus_. _Belemnitidoe_. _Belemnoteuthis_. _Belinurus_. _Bellerophon; Argo_. _Belodon; Carolinensis_. _Belosepia_. _Beloteuthis subcostata_. Bembridge Beds. _Beryx; Lewesiensis_. _Beyrichia; complicata_. Bird's-eye Limestone. Birds, of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Post-Pliocene. _Bison priscus_. Bituminous Schists of Caithness. Bivalves (_see_ Lamellibranchiata). Black-lead (_see_ Graphite). Black-River Limestone. _Blastoidea_; of the Devonian; of the Carboniferous. _Boidoe_. Bolderberg Beds. Bone-bed, of the Upper Ludlow; of the Trias. Bony Fishes (_see_ Teleostean Fishes). _Bos primigenius; _taurus_. Boulder-clay. _Bourgueticrinus_. Bovey-Tracy Beds. _Brachiopoda_; of the Cambrian rocks; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene. _Brachymetopus_. Brachyurous Crustaceans. Bradford Clay. Breaks in the Geological and Palæontological record. Breccia. Brick-earths. Bridlington Crag. Brittle-stars (_see_ Ophiuroidea). _Bronteus_. _Brontotheridoe_. _Brontotherium ingens_. _Brontozoum_. _Buccinum_. _Bucklandia_. _Bulimus_. Bunter Sandstein. Butterflies. _Byssoarca_.

Cainozoic (_see_ Kainozoic). Calamaries. _Calamites; cannoeformis_. Calcaire Grossier. Calcareous rocks; Tufa. Calciferous Sand-rock. _Calveria_. _Calymene; Blumenbachii_. _Camarophoria globulina_. Cambrian period; rocks of, in Britain; in Bohemia; in North America; life of. _Camelopardalidoe_. Camels. _Canis lupus; Parisiensis_. Caradoc rocks. Carbon, origin of. Carboniferous Limestone. Carboniferous period; rocks of; life of. Carboniferous Slates of Ireland. _Carcharias_. _Carcharodon; productus_. _Cardinia_. _Cardiocarpon_. _Cardiola; fibrosa; interrupta_. _Cardita; planicosta_. _Cardium; Rhoeticum_. Caribou. _Carnivora_, of the Eocene; of the Miocene; of the Pliocene; of the Post-Pliocene. _Caryocaris_. _Caryocrinus ornatus_. _Castor fiber_. _Castoroides Ohioensis_. Catastrophism, theory of. _Catopterus_. Cauda-Galli Grit. _Caulopteris_. Cave-bear. Cave-deposits. Cave-hyæna. Cave-lion. Caves, formation of; deposits in. _Cavicornia_. Cement-stones. _Cephalaspis_. _Cephalopoda_, of the Cambrian period; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. _Ceratiocaris_. _Ceratites; nodosus_. _Ceratodus; altus; Fosteri; serratus_. _Ceriopora; Hamiltonensis_. _Cerithium; _hexagonum_. _Cervidoe_, of the Miocene period; of the Pliocene; of the Post-Pliocene. _Cervus; capreolus; elaphus; megaceros; tarandus_. _Cestracion Philippi_. Cestracionts, of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous. _Cetacea_; of the Eocene; of the Miocene. _Cetiosaurus_. _Choeropotamus_. _Choetetes; tumidus_. Chain-coral. Chalk; structure of; Foraminifera of; origin of; with flints; without flints. _Chama_. _Chamoerops; Helvetica_. Chazy Limestone. _Cheiroptera_, of the Eocene; of the Miocene. _Cheirotherium_. _Cheirurus; bimucronatus_. _Chelichnus Duncani_. _Chelone Benstedi; planiceps_. _Chelonia_, of the Permian; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. _Chemnitzia_. Chemung Group. Chert. Chillesford Beds. _Chonetes; Hardrensis_. _Chonophyllum_. _Cidaris_. Cincinnati Group. _Cinnamomum polymorphum_. Cinnamon-trees. _Cladodus_. Claiborne Beds. _Clathropora; intertexta_. Clay; Red, origin of. Clay-ironstone, nodules of. _Cleidophorus_. _Cleodora_. _Climacograptus_. Clinton Formation. _Clisiophyllum_. _Clupeidoe_. _Clymenia; Sedgwickii_. Coal; structure of; mode of formation of. Coal-measures; mineral characters of; mode of formation of; plants of. Coccoliths. _Coccosteus_. _Cochliodus; cantortus_. _Coleoptera_. _Colossochelys Atlas_. _Columnaria; alveolata_. _Comatula_. Conclusions to be drawn from Fossils. Concretions, calcareous; phosphatic; of clay-ironstone; of manganese. Conglomerate. _Coniferoe_; wood of; of Devonian period; of the Carboniferous; of the Permian; of the Trias; of the Jurassic period. Coniston Flags and Grits. Connecticut Sandstones, footprints of. _Conocoryphe Mathewi; Sultzeri_. Conodonts. _Constellaria_. Constricting serpents of the Eocene. Contemporaneity of strata. Continuity, theory of. _Conularia; ornata_. _Conulus_. _Conus_. Coomhola Grits. Coprolites. Coralline Crag. Corallines. _Corallium_. Coral-rag. Coral-reefs. Coral-rock. Coral-sand. Corals; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. _Corbula_. Cornbrash. Corniferous Limestone. _Cornulites_. Cornus. _Coryphodon_. Cowries. Crabs. Crag, Red; White; Norwich; Antwerp; Bridlington; Coralline. _Crania; Ignabergensis_. _Crassatella_. _Crepidophyllum; Archiaci_. Cretaceous period; rocks of, in Britain; in North America; life of. Crinoidal Limestone. _Crinoidea_; of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Triss; of the Jurassic; of the Cretaceous; of the Eocene. _Crioceras; cristatum_. _Crocodilia_; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene. Cromer Forest-bed. _Crossozamites_. _Crotalocrinus_. _Crustacea_, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous. Cryptogams. _Ctenacanthus_. _Ctenodonta_. _Cupressus_. Cursores. Cuttle-fishes (_see_ Dibranchiate Cephalopods). _Cyathocrinus_. _Cyathophyllum_. _Cycadopteris_. Cycads; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous. _Cyclas_. _Cyclonema_. _Cyclophthalmus senior_. _Cyclostoma; Arnoudii_. _Cynodraco_. _Cyproea; elegans_. Cypress. _Cypridina_. Cypridina Slates. _Cyrena_. _Cyrtina_. _Cyrtoceras_. _Cystiphyllum; vesiculosum_. _Cystoidea_; of the Cambrian; of the Lower Silurian; of the Upper Silurian.

Dachstein Beds. _Dadoxylon_. _Daonella; Lommelli_. _Dasornis Londinensis_. Decapod Crustaceans. Deer. _Deinosauria_; of the Trias; of the Jurassic; of the Cretaceous. _Deinotherium; giganteum_. Denbighshire Flags and Grits. _Dendrocrinus_. _Dendrograptus_. Desmids. Devonian Formation; origin of name; relation to Old Red Sandstone; of Devonshire; of North America; life of. _Diadema_. Diatoms; of the Devonian; of the Carboniferous; of flints; of Richmond Earth. Dibranchiate Cephalopods; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. _Diceras; arietina_. Diceras Limestone. _Dichobune_. _Dichograptus; octobrachiatus_. Dicotyledonous plants. _Dicotyles antiquus_. _Dicranograptus_. _Dictyonema; sociale_. _Dicynodon; lacerticeps_. _Didelphys; gypsorum_. _Didus ineptus_. _Didymograptus; divaricatus_. _Dikellocephalus Celticus; Minnesotensis_. _Dimorphodon_. _Dinichthys; Hertzeri_. _Ditoceras; mirabilis_. _Dinocerata_. _Dinophis_. _Dinornis; elephantopus; giganteus_. _Dinosauria_ (see _Deinosauria_). _Dinotherium_ (see _Deinotherium_). _Diphyphyllum_. _Diplograptus; pristis_. _Dipnoi_. _Diprotodon; australis_. _Diptera_. _Discina_. _Discoidea; cylindrica_. _Dithyrocaris; Scouleri_. Dodo. Dog whelks. Dolomite. Dolomitic Couglomerate of Bristol. Dolphins. _Dorcatherium_. Downton Sandstone. _Draco volans_. Dragon-flies. Drift, Glacial. _Dremotherium_. _Dromatherium sylvestre_. _Dryandra_. _Dryopithecus_. Dugougs.

_Echinodermata_, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene. _Echinoidea_; of the Upper Silurian; or the Devonian; of the Carboniferous; of the Permian; of the Jurassic; of the Cretaceous. _Edentata_; of the Eocene; of the Miocene; of the Post-Pliocene. _Edriocrinus_. Eifel Limostone. _Elasmobranchii_ (_See_ Placoid Fishes). _Elasmosaurus_. Elephants. _Elphas; Americanus; antiquus; Falconeri; Melitensis; meridionalis; planifrons; primigenius_. Elk; Irish. _Ellipsocephalus Hoffi_. _Elotherium_. _Emydidoe_. _Emys_. Enaliosaurians. Encrinital warble. _Encrinurus_. _Encrinus liliiformis_. Endogenous plants. _Endophyllum_. _Endothyra; Bailyi_. Engis skull. _Entomis_. _Entomoconchus Scouleri_. Eocene period; rocks of, in Britain; in France; in North America; life of. _Eocidaris_. _Eophyton; Linneanum_. Eophyton Sandstone. _Eosaurus Acadianus_. Eozoic rocks. _Eozoön Bavaricum_. _Eozoön Canadense_; appearance of, in mass; minute structure of; affinities of, with _Foraminifera_. _Ephemeridoe_. _Equisetaceoe_. _Equisetites_. _Equidoe_. _Equus; caballus; excelsus; fossilis_. _Eridophyllum_. _Eryon arctiformis_. _Eschara_. _Escharidoe_. _Escharina; Oceani_. _Estheria; tenella_. _Eucalyptocrinus; polydactylus_. _Eucladia_. _Euomphalus; discors_. _Euplectella_. _Euproöps_. European Bison. _Eurypterida_; of the Upper Silurian; of the Devonian. Even-toed Ungulates. Exogenous plants. _Exogyra; virgula_. Extinction of species.

_Fagus_. Faluns. Fan-palms. _Favistella_. _Favostites; Gothlandica; hemisphoerica_. Faxöe Limestone. _Felis angustus; leo; speloea_. _Fenestella; cribrosa; magnifica; retiformis_. _Fenestellidoe_. Ferns, of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous. Fig-shells. Fishes; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. Flint; structure of; origin of; organisms of; of Chalk. Human implements associated with bones of extinct Mammals. Flora (_see_ Plants). Footprints of _Cheirotherium_; of the Triassic sandstones of Connecticut. _Foraminifera_; of the Cambrian; of the Lower Silurian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene; of the Post-Pliocene; of Atlantic ooze; as builders of limestone; as forming green sands. _Forbesiocrinus_. Forest-bed of Cromer. Forest-bugs. Forest-marble. Formation, definition of; succession of. Fossiliferous rocks; chronological succession of. Fossilisation, processes of. Fossils, definition of; distinctive, of rock-groups; conclusions to be drawn from; biological relations of. Foxes. Fringe-finned Ganoids. Fucoidal Sandstone. Fucoids. Fuller's Earth. _Fusulina; cylindrica_. _Fusus_.

_Galeocerdo_. _Galerites; albo-galerus_. _Galestes_. Ganoid Fishes; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene. Gaspé Beds. _Gasteropoda_, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene. _Gastornis Parisiensis_. Gault. Gavial. Genesee Slates. Geological record, breaks in the. Giraffes. Glacial period; deposits of. _Glandulina_. Glauconite. _Glauconome; pulcherrima_. Globe Crinoids (_see_ Cystoidea). _Globigerina_. Glutton. _Glyptaster_. _Glyptocrinus_. _Glyptodon; clavipes_. _Glyptoloemus_. Goats. _Goniatites; Jossoe_. _Gorgonidoe_. _Grallatores_. Graphite; mode of occurrence of; origin of. _Graptolites_; structure of; of the Lower Silurian; of the Upper Silurian. Great Oolite; Upper. Greenland. Miocene plants of. Greensand, Lower. Green sands, origin of. _Grevillea_. _Griffithides_. Grizzly Bear. Groond Sloths. _Gryphoea; incurva_. Guelph Limestone. _Gulo luscus; speloeus_. Guttenstein Beds. Gymnospermous Exogens. Gypsum. _Gyracanthus_. _Gyroceras_.

_Hadrosaurus_. _Halitherium_. Hallstadt Beds. _Halobia_. _Halysites; agglomerata; catenularia_. Hamilton formation. _Hamites; rotundus_. _Haplophlebium Barnesi_. Harlech Grits. _Harpes; ungula_. Hastings Sands. Headon and Osborne series. Heart-urchins. _Heliolites_. _Heliophyllum; exiguum_. _Helix_. _Helladotherium_. _Helopora fragilis_. _Hemicidaris crenularis_. _Hemiptera_. _Hemitrochiscus paradoxus_. Hempstead Beds. _Hesperornis; regalis_. _Heteropoda_; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous. _Hinnites_. _Hipparion_. _Hippopodium_. _Hippopotamus; amphibus; major; Sivalensis_. _Hippothoa_. Hippurite Marble. _Hippurites; Toucasiana_. _Hippuritidoe_. _Histioderma_. Hollow-horned Ruminants. _Holocystis elegan_. _Holopea; Subconica_. _Holopella; obsoleta_. _Holoptychius; nobilissimus_. Holostomatous Univalves. Holothurians. _Holtenia_. _Homacanthus_. _Homalonotus; armatus_. _Homo diluvii testis_. Honeycomb Corals. Hoofed Quadrupeds. Hudson River Group. Huronian Period; rocks of. _Hyoena crocuta; speloea; Hipparionum_. _Hyoenictis_. _Hyoenodon_. _Hyalea D'Orbignyana_. _Hybodus_. _Hydractinia_. Hydroid Zoophytes. _Hymenocaris vermicauda_. _Hymenophyllites_. _Hymenoptera_. _Hyopotamus_. _Hyperodapedon_. _Hypsiprymnopsis_. _Hystrix primigenius_.

_Ichthyocrinus loevis_. _Ichthyornis; dispar_. _Ichthyosaurus; communis_. _Ictitherium_. _Iguana_. _Iguanodon; Mantelli_. Ilfracombe Group. _Illoenus_. Imperfection of the palæontological record. Inferior Oolite. Infusorial Earth. _Inoceramus; sulcatus_. _Insectivora_, of the Eocene; of the Miocene. Insects, of the Devonian; of the Carboniferous; of the Jurassic; of the Miocene. Irish Elk. _Ischadites_. Isopod Crustaceans.

Jackson Beds. Jurassic period; rocks of; life of.

_Kaidacarpum_. Kainozoic period. Kangaroo. Kelloway Rock. Kent's Cavern, deposits in. Keuper. Kimmeridge Clay. King-crabs. _Koninckia_. Kössen Beds.

_Labyrinthodon Joegeri_. _Labyrinthodontia_; of the Carboniferous; of the Permian; of the Trias. Lace-corals. _Lacertilia_; of the Permian; of the Trias; of the Jurassic; of the Cretaceous. _Loelaps_. _Lamellibranchiata_, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene. _Lamna_. Lamp-shells (see _Brachiopoda_). Land-tortoises. _Lauraceoe_. Laurentian period; rocks of; Lower Laurentian; Upper Laurentian; areas occupied by Laurentian rocks; limestones of; iron-ores of; phosphate of lime of; graphite of; life of. Leaf-beds of the Isle of Mull. _Leda; truncata_. _Leguminosites Marcouanus_. Lemming. _Lepadidoe_. _Lepadocrinus Gebhardi_. _Leperditia; canadensis_. _Lepidaster_. _Lepidechinus_. _Lepidesthes_. Lepidodendroids. _Lepidodendron; Sternberg_. _Lepidoptera_. _Lepidosiren_. _Lepidosteus_. _Lepidostrobus_. _Lepidotus_. _Leptoena; Liassica; sericea_. _Leptocoelia; plano-convexa_. Lias. Lichas. _Licrophycus Ottawaensis_. Lignitic Formation of North America. Lily-encrinite. _Lima_. Lime, phosphate of. Limestone; varieties of; origin of; microscopical structure of; Crinoidal; Foraminiferal; coralline; magnesian; metamorphic; oolitic; pisolitic; bituminous; Laurentian. _Limnoea; pyramidalis_. _Limulus_. _Lingula; Credneri_. Lingula Flags. _Lingulella; Davisii; ferruginea_. _Liriodendron; Meeki_. _Lithostrotion; irregulare_. _Lituites_. Lizards (see _Lacertilia_). Llama. Llanberis Slates. Llandeilo rocks. Llandovery rocks; Lower; Upper. Lobsters. Loess. London Clay. Longmynd rocks. _Lonsdaleia_. _Lophiodon_. _Lophophyllum_. Lower Cambrian; Chalk; Cretaceous; Devonian; Eocene; Greensand; Helderberg; Laurentian rocks; Ludlow rock; Miocene; Old Red Sandstone; Oolites; Silurian period; rocks of, in Britain; in North America; life of. _Loxonema_. Ludlow rock. _Lycopodiaceoe_. Lynton Group. _Lyrodesma_.

Macaques. _Machoeracanthus major_. _Machairodus; cultridens_. _Maclurea; crenulata_. _Macrocheilus_. _Macropetalichthys; Sullivanti_. _Macrotherium giganteum_. _Macrurous Crustaceans_. _Mactra_. Maestricht Chalk. Magnesian Limestone; nature and structure of; of the Permian series. Magnolia. _Mammalia_, of the Trias; of the Jurassic; of the Eocene; of the Miocene; of the Pliocene; of the Post-Pliocene. Mammoth. Man, remains of, in Post-Pliocene deposits. Manatee. _Mantellia; megalophylla_. Maple. Marble; encrinital; statuary. Marcellus Shales. _Mariacrinus_. Marmots. Marsupials; of the Trias; of the Jurassic; of the Eocene; of the Miocene; of the Post-Pliocene. _Marsupiocrinus_. _Marsupites_. _Mastodon; Americanus, angustidens; Arvenensis; longirostris; Ohioticus; Sivalensis_. Medina Sandstone. _Megalichthys_. _Megalodon_. _Megalomus_. _Megalonyx_. _Megalosaurus_. _Megatherium; Cuvieri_. _Melania_. _Melonites_. Menevian Group. _Menobranchus_. _Meristella; cylindrica; intermedia; naviformis_. _Mesopithecus_. Mesozoic Period. _Michelinia_. _Micraster_. _Microlestes; antiquus_. Middle Devonian; Eocene; Oolites; Silurian. Miliolite Limestone. _Millepora_. Millstone Grit. Miocene period; rocks of, in Britain; in France; in Belgium; in Switzerland; in Austria; in Germany; in Italy; in India; in North America; life of. Mitre-shells. _Mitra_. Moas of New Zealand. _Modiolopsis; Solvensis_. Molasse. Mole. Monkeys. Monocotyledonous plant. _Monograptus; priodon_. _Monotis_. Monte Bolca, fishes of. _Montlivaltia_. Mosasauroids. _Mosasaurus; Camperi; princeps_. Mountain Limestone. Mud-fishes. Mud-turtles. Mull, Miocene strata of. _Murchisonia; gracilis_. _Murex. Muschelkalk. Musk-deer. Musk-ox. Musk-sheep. _Myliobatis Edwardsii_. _Mylodon; robustus_. _Myophoria; lineata_. _Myriapoda_ of the Coal.

_Nassa_. _Natatores_. _Natica_. _Nautilus; Danicus; pompilius_. Neanderthal skull. Neocomian series. _Neolimulus_. _Nerinoea; Goodhallii_. _Nerita_. _Neuroptera_. _Neuropteris_. Newer Pliocene. New Red Sandstone. Newts. Niagara Limestone. _Nipadites; ellipticus_. _Noeggerathia_. Norwich Crag. _Nothosaurus; mirabilis_. _Notidanus_. _Numenius gypsorum_. _Nummulina; loevigata; pristina_. _Nummulitic Limestone_.

Oak. _Obolella; sagittalis_. Odd-toed Ungulates. _Odontaspis_. _Odontopteris; Schlotheimi_. _Odontopteryx; toliapicus_. _Odontornithes_. _Ogygia; Buchii_. Older Pliocene. _Oldhamia; antiqua_; slates of Ireland. Old Red Sandstone; origin of name; of Scotland; relations of, to Devonian. _Olenus; micrurus_. Oligocene. _Oligoporus_. Olive-shells. _Omphyma_. _Onchus; tenuistriatus_. Oneida Conglomerate. _Onychodus; sigmoides_. Oolitic limestone, structure of; mode of formation of. Oolitic rocks (_see_ Jurassic). Ooze, Atlantic. _Ophidia_; of the Eocene. _Ophiuroidea_, of the Lower Silurian; of the Upper Silurian; of the Carboniferous; of the Trias; of the Jurassic. Opossum. _Orbitoides_. Oriskany Sandstone. _Ormoxylon_. _Orohippus_. _Orthis; biforata; Davidsoni; elegantula; flabellulum; Hicksii; lenticularis; plicatella; resupinata; subquadrala; testudinaria_. _Orthoceras; crebriseptum_. _Orthonota_. _Orthoptera_. _Osmeroides; Mantelli_. _Osmerus_. _Ostealepis_. _Ostracode_ Crustaceans of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous. _Ostrea acuminata; Couloni; deltoidea; distorta; expansa, gregarea; Marshii_. _Otodus; obtiquus_. _Otozamites_. _Otozoum_. _Oudenodon; Bainii_. _Ovibos moschatus_. Oxford Clay. _Oxyrhina; xiphodon_. Oysters.

_Pachyphyllum_. _Paloearca_. _Paloeaster; Ruthveni_. _Palasterina; primoeva_. _Paloechinus; ellipticus_. _Paloeocaris; typus_. _Paloeocoma; Colvini_. _Paloeocoryne_. Palæolithic man, remains of. _Paloeomanon_. _Paloeoniscus_. _Paloeontina Oolitica_. Palæontological evidence as to Evolution. Palæontological record, imperfection of the. Palæontology, definition of. _Paloeonyctis_. _Paloeophis; toliapictus; typhoeus_. _Paloeoreas_. _Paloeosaurus; platyodon_. _Paloeosiren Beinerti_. _Paloeotherium; magnum_. _Paloeoxylon_. Palæozoic period. Palms. _Paludina_. _Pandaneoe_. _Pandanus_. _Paradoxides; Bohemicus_. _Parasmilia_. _Parkeria_. Pear Encrinite. Pearly Nautilus. Peccaries. _Pecopteris_. _Pecten Groenlandicus; Islandicus; Valoniensis_. Penarth Beds. _Pennatulidoe_. _Pentacrinus; caput-medusoe; fasciculosus_. _Pentamerus; galeatus; Knightii_. _Pentremites_ (_see_ Blastoidea). _Pentremites conoideus; pyriformis_. Perching Birds. _Percidoe_. _Periechocrinus_. _Perissodactyle Ungulates_. Permian period; rocks of, in Britain; in North America; life of. Persistent types of life. _Petalodus_. _Petraster_. Petroleum, origin of. Pezophaps. _Phacops; Downingioe; granulatus; loevis; latifrons; longicaudatus; rana_. _Phoenopora ensiformis_. Phalangers. Phanerogams. _Phaneropleuron_. _Phascolotherium_. _Pheronema_. _Phillipsastroea_. _Phillipsia; seminifera_. _Pholadomya_. _Phormosoma_. _Phorus_. Phosphate of lime, concretions of; disseminated in rocks; origin of. _Phyllograptus; typus_. _Phyllopoda_, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias. _Phyllopora_. _Physa; columnaris_. Pigs. Pilton Group. _Pinites_. _Pisces (_see_ Fishes). _Pisolite_. Pisolitic Limestone of France. _Placodus; gigas_. Placoid Fishes; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. _Plagiaulax_. _Planolites; vulgaris_. _Planorbis_. Plants, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. _Plasmopora_. _Platanus; aceroides_. _Platephemera antiqua_. _Platyceras; dumosum; multisinuatum; ventricosum_. _Platycrinus; tricontadactylus_. _Platyostoma; Niagarense_. Platyrhine Monkeys. _Platyschisma helicites_. _Platysomus; gibbosus_. _Platystoma_. Pleistocene period; climate of. _Plesiosaurus; dolichodeirus_. _Pleurocystites squamosus_. _Pleurotoma_. _Pleurotomaria_. _Plicatula_. Pliocene period; rocks of, in Britain; in Belgium; in Italy; in North America; life of. _Pliopithecus; antiquus_. _Pliosaurus_. _Podocarya_. _Podozamites; lanceolatus_. Polir-schiefer. _Polycystina_; of Barbadoes-earth. _Polypora; dendroides_. _Polypterus_. _Polystomella_. _Polytremacis_. _Polyzoa_, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Cretaceous; of the Miocene. _Populus_. _Porcellia_. Porcupines. Portage Group. Port-Jackson Shark. Portland beds. Post-Glacial deposits. Post-Pliocene period. Post-Tertiary period. _Poteriocrinus_. Potsdam Sandstone. Pre-Glacial deposits. _Prestwichia; rotundata_. _Primitia; strangulata_. Primordial Trilobites. Primordial zone. _Proboscidea_, of the Miocene; of the Pliocene; of the Post-Pliocene. _Producta; horrida; longispina; semireticulata_. _Productella_. _Productidoe_. _Proëtus_. Prong-buck. _Protaster; Sedgwickii_. _Proteaceoe_. _Proteus_. _Protichnites_. _Protocystites_. _Protornis Glarisiensis_. _Protorosaurus; Speneri_. _Protospongia; fenestrata_. _Prototaxites; Logani_. _Psammobia_. _Psammodus_. _Psaronius_. _Pseudocrinus bifasciatus_. _Psilophyton; princeps_. _Pteranodon; longiceps_. _Pteraspis; Banksii_. _Pterichthys; cornutus_. _Pterinoea; subfalcata_. _Pteroceras_. _Pterodactylus; crassirostris_. _Pterophyllum; Joegeri_. _Pteropoda_, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Jurassic. _Pterosauria_; of the Jurassic; of the Cretaceous. _Pterygotus Anglicus_. _Ptilodictya; acuta; falciformis; raripora; Schafferi_. _Ptychoceras; Emericianum_. _Ptychodus_. _Pupa vetusta_. Purbeck Beds; Mammals of. _Puryuroidea_. _Pycnodus_. _Pyrula_.

_Quadrumana_, of the Eocene; of the Miocene; of the Pliocene; of the Post-Pliocene. Quadrupeds (_see_ Mammalia). Quaternary period. Quebec Group. _Quercus_.

Rabbits. _Rana_. _Raptores_. _Rasores_. Recent period. _Reptaculites_. Red clays, origin of. Red Coral. Red Crag. Red Deer. Reindeer. _Remopleurides_. Reptiles; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene. _Retepora; Ehrenbergi; Phillipsi_. _Retiolites_. _Retzia_. _Rhætic Beds_. _Rhamphorhynchus; Bucklandi_. _Rhinoceridoe_. _Rhinoceros Etruscus; leptorhinus; megarhinus; tichorhinus_. _Rhinopora verrucosa_. _Rhizodus_. _Rhombus minimus_. Rhyncholites. _Rhynchonella; cuneata; neglecta; pleurodon; varians. _Rhynchosaurus; articeps. Rice-shells. Richmond Earth. Ringed Worms (_see_ Annelida). River-gravels, high-level and low-level. _Robulina_. Rocks, definition of; divisions of; igneous; aqueous; mechanically-formed; chemically-formed; organically-formed; arenaceous; argillaceous; calcareous; siliceous. _Rodentia_, of the Eocene; of the Miocene; of the Post-Pliocene. Roebuck. _Rostellaria_. _Rotalia; Boueana_. Rugose Corals; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Upper Greensand. Rupelian Clay.

_Sabal major_. Sabre-toothed Tiger. _Saccammina_. _Saccosoma. Salamanders. Salina Group. _Salix; Meeki_. _Salmonidoe_. _Sao hirsuta_. _Sassafras cretacea_. _Sauropterygia_. _Scalaria; Groenlandica_. _Scaphites; oequalis_. _Schizodus_. Schoharie Grit. _Scolecoderma_. _Scoliostoma_. _Scolithus; Canadensis_. Scorpions of the Coal-measures. Scorpion-shells. Screw-pines. _Scutella; subrotunda_. Sea-cows (_see_ Sirenia). Sea-lilies (_see_ Crinoidea). Sea-lizards (_see_ Enaliosaurians). Seals. Sea-mats and Sea-mosses (_see_ Polyzoa). Sea-shrubs (_see_ Gorgonidæ). Sea-urchins (_see_ Echinoidea). Sea-weeds. Secondary period. Sedimentary rocks. _Semnopithecus_. Septaria. _Sequoia; Couttsioe; gigantea; Langsdorffii_. _Serolis_. Serpents (_see_ Ophidia). _Serpulites_. Sewâlik Hills (_see_ Siwâlik Hills). Sheep. Shell-sands. _Sigillaria; Groeseri_. Sigillarioids. Silicates, infiltration of the shells of Foraminifera by. Siliceous rocks. Siliceous Sponges. Silicification. Silurian period (_see_ Lower Silurian and Upper Silurian). _Simosaurus; Gaillardoti_. _Siphonia; ficus_. Siphonostomatous Univalves. _Siphonotreta_. _Sirenia_; of the Eocene; of the Miocene. _Siren lacertina_. _Sivatherium; giganteum_. Siwâlik Hills, Miocene strata of. Skiddaw Slates. Sloths. _Smilax_. _Smithia_. Snakes (_see_ Ophidia). Soft Tortoises. _Solarium_. Solenhofen Slates. Solitaire. _Spalacotherium_. _Spatangus_. _Sphoerospongia_. _Sphagodus_. _Sphenodon_. _Sphenopteris_. Spiders of the Coal-measures. Spider-shells. Spindle-shells. _Spirifera; crispa; disjuncta; hysterica; mucronata; Niagarensis; rostrata; sculptilis; trigonalis_. _Spiriferidoe_. _Spirophyton cauda-Galli_. _Spirorbis; Arkonensis; Carbonarus; laxus; Lewisii; omphalodes; spinulifera_. _Spirulirostra_. _Spondylus; spinosus_. Sponges, of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous. _Spongilla_. _Spongillopsis_. _Spongophyllum_. Spore-eases, of Cryptogams in the Ludlow rocks; in the Coal. Squirrels. _Stagonolepis_. Staircase-shell. Stalactite. Stalagmite. Star-corals. Star-fishes. St Cassian Beds. _Stephanophyllia_. _Stereognathus_. _Stigmaria; ficoides_. Stonesfield Slate; Mammals of. Strata, contemporaneity of. Stratified rock. _Streptelasma_. _Streptorhynchus_. _Stromatopora; rugosa; tuberculata_. _Strombodes; pentagonus_. _Strombus_. _Strophalosia_. _Strophodus_. _Strophomena; alternata; deltoidea; filitexta; rhomboidalis; Subplana_. Sub-Apennine Beds. Sub-Carboniferous rocks. Succession of life upon the globe. _Suida_. Sulphate of lime. _Sus Erymanthius; scrofa_. _Synastroea_. _Synhelia Sharpeana_. _Synocladia; virgulacea_. _Syringopora; ramulosa_.

Tabulate Corals; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian. _Talpa Europoea_. _Tapiridoe_. Tapirs. _Tapirus Arvernensis_. _Taxocrinus tuberculatus_. _Taxodium_. _Teleosaurus_. Teleostean Fishes; of the Cretaceous. _Telerpeton Elginense_. _Tellina proxima_. _Tentaculites; ornatus_. _Terebra_. _Terebratella; Astleriana_. _Terebratula; digona; elongata; hastata; quadrifida; sphoeroidalis_. _Terebratulina; caput-serpentis; striata_. Termites. Terrapins. Tertiary period. Tertiary rocks, classification of. _Testudinidoe_. Tetrabranchiate Cephalopods; of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous; of the Permian; of the Trias; of the Jurassic; of the Cretaceous; of the Eocene; of the Miocene. _Textularia; Meyeriana_. Thanet Sands. _Theca_. _Theca Davidii_. _Thecidium_. Thecodont Reptiles. _Thecodontosaurus; antiquus_. _Thecosmilia annularis_. _Thelodus_. Theriodont Reptiles. _Thylacoleo_. Tile-stones. _Titanotherium_. Toothed Birds. Tortoises. _Tragoceras_. Travertine. Tree-Ferns, of the Devonian; of the Coal-measures. Tremadoc Slates. _Trematis_. Trenton Limestone. _Trianthrus Beckii_. Triassic period; rocks of, in Britain; in Germany; in the Austrian Alps; in North America; life of. _Triconodon_. _Trigonia_. _Trigoniadoe_. _Trigonocarpum; ovatum_. Trilobites; of the Cambrian; of the Lower Silurian; of the Upper Silurian; of the Devonian; of the Carboniferous. _Trimerellidoe_. _Trinucleus; concentricus_. _Trionycidoe_. _Triton_. _Trochocyathus_. _Trochonema_. _Trogontherium; Cuvieri_. Trumpet-shells. Tulip-tree. _Turbinolia sulcata_. _Turbinolidoe_. _Turrilites; catenulatus_. _Turritella_. Turtles. _Typhis tubifer_.

_Ullmania selaginoides_. Unconformability of strata. Under-clay of coal. _Ungulata_, of the Eocene; of the Miocene; of the Pliocene; of the Post-Pliocene. Uniformity, doctrine of. _Unio_. Univalves (_see_ Gasteropoda). Upper Cambrian; Chalk; Cretaceous; Devonian; Eocene; Greensand; Helderberg; Laurentian; Llandovery; Ludlow rock; Miocene; Oolites; Silurian period; rocks of, in Britain; in North America; life of. _Ursus arctos; Arvernensis; ferox; speloea_. _Ursus_.

Valley-gravels, high-level and low-level. _Vanessa Pluto_. _Varanidoe_. Vegetation (_see_ Plants). _Ventriculites; simplex_. Venus's Flower-basket. _Vermilia_. _Vespertilio Parisiensis_. Vicksburg Beds. Vines. Vitreous Sponges. _Voltzia; heterophylla_. _Voluta; elongata_. Volutes.

_Walchia; piniformis_. Walrus. Wealden Beds. _Wellingtonia_. Wenlock Beds; Limestone; Shale. Wentle-traps. Werfen Beds. Whalebone Whales. Whales. Whelks. White Chalk; structure of; origin of. White Crag. White River Beds. Wild Boar. _Williamsonia_. Winged Lizards (_see_ Pterosauria). Winged Snails (_see_ Pteropods). Wing-shells. Wolf. Wolverine. Wombats. Woolhope Limestone. Woolly Rhinoceros. Woolwich and Reading Beds. Worm-burrows.

_Xanthidia_. _Xenoneura antiquorum_. _Xiphodon_. _Xylobius; Sigillarioe_.

_Zamia spiralis_. _Zamites_. _Zaphrentis; cornicula; Stokesi; vermicularis_. _Zeacrinus_. Zechstein. _Zeuglodon; cetoides_.