CHAPTER XII.

[Sidenote: ARGONAUTA. NAUTILUS.]

"So many families of the fourth order, _Cephalopoda_, are found only in a fossil state, and which you will not easily meet with, that I shall not consider it needful to give you the whole catalogue," observed Mr. Elliot to his young pupils at the beginning of the next lesson.

"But we are exceedingly interested about fossils," replied Charles; "pray do not pass any species that we may be likely to find."

"And I," said Lucy, "have much wished to ask whether the _snake-stone_ ever was a shell? it is something like a _Planorbis_, but heavy and imperfect."

"I will answer your question presently," said her father. "Tell me what genera remain to be noticed among the univalves of Linnæus?"

"_Argonauta_ and _Nautilus_," was the ready reply.

"The animals inhabiting these shells are _Cephalopoda_. The word indicates the position of the feet, or more properly _arms_ of the animal, which are ranged round the head like a crown. The body is thick and fleshy, contained in a kind of bag, whence the head issues, surrounded by these arms, which vary in different genera.

[Sidenote: CUTTLE-FISH. BELEMNITE. SPIRULA.]

"The common _cuttle-fish_, a native of our seas, will give you an idea of a cephalopode.

"In the first family a fossil-shell occurs that is very frequently met with.

"Family, _Orthocerata_; genus, _Belemnite_, thunder-stone, or arrow-head. These fossil-shells occur abundantly in the chalk formations. Many superstitious notions have been attached to this extinct marine animal: of these you will find an account in the 'Penny Cyclopædia.'

"In the family _Lituolita_ we meet with the delicate and remarkable little shell _Spirula Peronii_, distinct from _Nautilus_ by the separation of the volutions: it is nearly covered by the body of the animal. The colour is white; the texture thin and brittle: it has a lateral syphon, the orifice of which is very clearly to be seen as each compartment is taken off. There is but one species; it is found in the Southern Ocean and the Moluccas. The shells are seen floating on the surface of the water when the animal is dead, and are sometimes carried to the shore. (Plate 9.)

[Sidenote: AMMONITE. NAUTILUS.]

"Another family of this order, _Nautilacea_, contains, among many other genera, the celebrated _Nautilus_. This genus, you are already informed, is distinguished from _Argonauta_ by its shells being many-chambered. Two or three fossil species have been found in London clay.

"Among the various fossil-shells abounding in different strata, not known in a recent state, the one most remarkable and frequently occurring is the Ammonite, _Cornu Ammònis_, so called from the resemblance it bears to the convoluted horns of Jupiter Ammon, in mythological history. This is your _snake-stone_, Lucy, a local name, which you had better change for Ammonite. Various legends are connected with this fossil, of which you may obtain information by consulting the before-mentioned publication.

"As you are desirous of studying geology, a knowledge of the Ammonites is very requisite, since whole sections of the genus are characteristic of certain strata.

"They are nearly allied to the _Nautilus_. The species are very numerous; one hundred and twenty according to some authors--two hundred and seventy species are enumerated by others. They occur in Europe, Asia, and America: they have been found in the chalk with a diameter of three feet.

"In the second division of this order the genus _Argonauta_ occurs: the shell has been already described, and retains its original name. (Plate 6.)

[Sidenote: OCTOPUS. LOLIGO. SEPIA.]

"In the third division is the family _Sepiaria_, containing _Octopus_, _Lolìgo_, and _Sepia_. This section contains animals without shells. _Octopus vulgàris_ is common in the European seas. In hot climates it grows to a very large size. The animal has sufficient strength to draw a boat under water.

"_Lolìgo_ also is found in our seas; the thin, transparent rib, called the _dorsal blade_, you may probably find on the shore, the flesh that covered the blade being cleared entirely from it. The colour is either white or brown. It is called _sea-sleeve_.

"The bone of the cuttle-fish, _Sepia officinalis_, is so frequently thrown on shore by the waves, that few persons visiting the sea-coast can be ignorant of its form. You have a large collection there I see, Lucy; and you are doubtless aware that this calcareous bone affords the _pounce_ of the stationers, when finely pulverized: it also forms one ingredient of tooth-powder.

"The ink of this marine animal is contained in a bag: the use of the fluid is to colour the water around, in order to conceal itself from hostile attack. The flesh of some of these animals is used for food, and is frequently seen in the market at Naples. In the British isles it is not put to any culinary purpose. The ink of _Sepia_ can be prepared for a pigment, or paint.

"The fifth and last order of the twelfth class is _Heteropoda_, which contains only a few genera, one of which I shall notice.

[Sidenote: CARINARIA.]

"_Carinaria_, the glass-nautilus, is a rare and very precious genus, containing but three species. The first, _Carinaria ritrea_, has been found in the Southern Ocean. There is a model of the shell in the British Museum; that of Paris possesses the shell itself.

"_C. Mediterranea_ is found in the neighbourhood of Nice, and is frequent in the summer months. So thin and delicate is the shell that it is seldom found entire.

"The shell of _Carinaria_ is wholly external, and is attached to the upper part of the body, apparently to protect the organs of respiration. The body is transparent, dotted with elevated points; on the lower part is a beautiful reticulated fin, of a reddish colour; with the end of this fin it floats along, carrying its delicate shell. The habit of the animal, which swims upon its back, reverses the natural position of the shell, which is on the upper part of the body when at rest."

"That is one of the most remarkable creatures you have yet mentioned," said Charles; "I may chance to meet with a specimen when I travel."

"Probably," replied Mr. Elliot; "but our lessons are now concluded--_Carinaria_ is the last genus."

"How greatly we are obliged to you, father!" said Lucy: "but I hope you will still give us a little advice and assistance: we shall often be unable to determine the genera of some shells, I am sure, especially among the bivalves."

[Sidenote: METHOD OF CLEANSING SHELLS.]

"Most willingly: but tell me if you know the easiest method of cleaning shells when they become soiled, or when you purchase them in the natural state?"

"That is a question I wished to ask."

"A little warm water and soap will cleanse and render them bright. Some collectors rub Florence oil over their shells, which prevents them from becoming dry. A weak solution of gum-arabic is sometimes applied, in order to produce a polished and bright appearance.

"Nitric or muriatic acid, diluted, is used to take off the epidermis, or any extraneous matter; but it must be done carefully, and the shell plunged in water after the acid has been applied. But do not make a practice of polishing; shells are best in their natural state, generally speaking."

"Thank you, father!" said both the young people.

"You are welcome to any instruction I can give you," he replied; "and now farewell for to-night."

A LIST OF SPECIES

_That may be purchased at a moderate Price._

Examples of the genera that may be easily obtained from the British Coast, or which are expensive, are omitted.

_Dentalium entalis._ _Pectinaria Belgica._[E] _Balanus tintinnabulum._ _Pentalasmis anatifera._ _Corbula nucleus._ _Psammobia virgata._ _Lucina carnaria._ _Cyprina Islandica._ _Cytherea chionè._ _Venus tigerina._ _Isocardia cor._ _Arca Noæ._ _Pectunculus marmoratus._ _Chama arcinella._ _Tridacna crocea._ _Pinna muricata._ _Perna ephippium._ _Meleagrina margaritacea._ _Lima squamosa._ _Spondylus gæderopus._ _Chiton squamosus._ _Emarginula fissura._ _Fissurella Græca._ _Pileopsis Hungarica._ _Calyptræa equestris._ _Bulla ampulla._ _Helix melanotragus._ _Pupa mummia._ _Bulimus ovatus._ _Achatina virginea._ _Neritina corona._ _Nerìta polìta._ _Natìca alba._ _Iànthina communis._ _Sigaretus haliotoideus._ _Pyramidèlla dolabrata._ _Scalària commùnis._ _Delphinula lacinìata._ _Solarium perspectivum._ _Trochus tuber._ _Monodonta labio._ _Turbo pica._ _Phasianella bulimoìdes._ _Cerithium vertagus._ _Pyrula ficus._ _Ranella crumèna._ _Murex haustèllum._ _Triton lotorium._ _Pterocera lambis._ _Strombus lineàtus._ _Cassis arèola._ _Ricinula horrida._ _Purpura patula._ _Monoceros imbricatum._ _Concholepas Peruvianus._ _Harpa ventricosa._ _Dolium maculàtum._ _Eburna spiràta._ _Terebra maculàta._ _Columbella mercatòria._ _Mitra episcopàlis._ _Voluta musica._ _Volraria monìlis._ _Ovula oviformis._ _Cypræa cribària._ _Terebellum subulàtum._ _Oliva utriculus._ _Conus virgo._ _Nautilus hians._ _Spirula Peronii._

[E] Or _Sabella_.

INDEX.

Page.

Acasta, 41 Acera, 64 Achatina, 69 Alata, 85 Ammonite, 103 Anatina, 47 Ancilla, 98 Ancylas, 64 Anodon, 54 Anomia, 29 Anostoma, 68 Annularia, 39 Aplysia, 65 Arca, 53 Argonauta, 29 Aspergillum, 45 Auricula, 69 Avicula, 57

Balanus, 40 Belemnite, 102 Bimusculosa, 44 Brachiopoda, 61 Buccinum, 32 Bulimus, 69 Bulla, 31

Calyptræa, 64 Cancellaria, 83 Capsa, 50 Caracolla, 68 Cardium, 23 Carinaria, 105 Cassis, 87 Cassidaria, 87 Cephalopoda, 101 Cerithium, 82 Chama, 26 Chamacea, 54 Chiton, 18 Cineras, 41 Cirrhipeda, 40 Clausilia, 69 Clavagella, 46 Cleodora, 62 Columbella, 91 Conchæ, 50 Conchifera, 44 Concholepas, 89 Conus, 30 Corbis, 50 Corbula, 48 Coronula, 40 Crassatella, 48 Crepidula, 64 Creusia, 41 Cyclas, 50 Cyclostoma, 69 Cymba, 92 Cypræa, 31 Cytherea, 52

Delphinula, 77 Dentalium, 36 Diceras, 54 Dolabella, 65 Dolium, 89 Donax, 23

Eburna, 90 Erycina, 48 Etheria, 54

Fasciolaria, 83 Fissurella, 64 Fusus, 84

Galeolaria, 40 Gasteropoda, 62 Gryphæa, 59

Haliotis, 35-75 Harpa, 89 Helix, 35-68 Heteropoda, 105 Hipponyx, 61

Ianthina, 74 Isocardia, 52

Lepas, 18 Lima, 58 Limax, 66 Lingula, 61 Litorina, 79 Loligo, 104 Lucina, 50 Lutraria, 48 Lymnæa, 71

Mactra, 23 Mactracea, 47 Magillus, 40 Melanopsis, 71 Meleagrina, 58 Melo, 92 Mitra, 92 Modiola, 56 Mollusca, 62 Monoceros, 89 Monodonta, 78 Murex, 35 Mya, 21 Myaria, 47 Mytilus, 27 Mytilacea, 56

Natica, 74 Navicella, 73 Nassa, 88 Nautilus, 30-103 Nerita, 35 Neritina, 73 Nucula, 53 Nymphacea, 49

Octopus, 104 Oliva, 98 Onchidium, 66 Orthocerata, 102 Ostrea, 26 Otion, 41 Ostracea, 59 Ovula, 93

Paludina, 72 Pandora, 48 Panopæa, 47 Parmacella, 66 Parmophorus, 64 Patella, 61-63 Pecten, 58 Pectunculus, 53 Perna, 57 Pentalasmis, 41 Phasianella, 79 Pileopsis, 64 Pinna, 57 Planorbis, 70 Placuna, 60 Plagiostoma, 58 Pleurotoma, 83 Plicatula, 59 Podopsis, 59 Pollicipes, 41 Potamophila, 51 Psammotæa, 49 Pterocera, 86 Pullastra, 51 Pupa, 69 Purpurifera, 87 Pyrgoma, 41 Pyrula, 84

Ranella, 84 Ricinula, 88 Rostellaria, 86 Rotella, 78 Rudista, 60

Sabella, 37 Scalaria, 76 Scapellum, 42 Serpula, 36 Sepia, 104 Siliquaria, 39 Sigaretus, 75 Solarium, 77 Solen, 22 Solenacea, 47 Spirorbis, 39 Spirula, 102 Spondylus, 25 Stomatia, 75 Stomatella, 75 Strombus, 33 Struthiolaria, 84 Succinea, 69

Tellina, 22-30 Terebellum, 97 Teredo, 46 Terebra, 91 Testacellus, 67 Trachelipoda, 67 Tridacna, 56 Trigoniana, 53 Trivia, 97 Triton, 85 Trochus, 78 Tubicinella, 40 Turbinella, 83 Turbo, 79

Umbrella, 63 Unio, 54 Unimusculosa, 56

Valvata, 71 Venus, 24-52 Venericardia, 52 Venerupis, 49 Vermetus, 76 Volvaria, 92 Voluta, 31 Vulsella, 60

Xylophaga, 46

THE END.

Joseph Rickerby, Printer, Sherbourn Lane.

* * * * *

Transcriber Notes

All illustrations were moved so as to not split paragraphs. Words with accented vowels were not standardized.

End of Project Gutenberg's Rudiments of Conchology, by Mary Anne Venning