Part 5

ACAMAS. Montfort. BELEMNITES multiforatus, Blainville. A species described as being perforated at the apex, by a stellated perforation. No species of Belemnite at present known agreeing with the description; it is supposed to have been taken from a broken specimen.

ACANTHOCHETES. A name given to a species of Chiton having bunches of bristles at the sides of the valves.

ACARDO. Commerçon. Described from a pair of bony plates, taken from the vertebræ of the Whale, and mistaken for a bivalve shell, destitute of a hinge.

ACARDO. Swainson. A generic term applied by Swainson to the nearly toothless species of Cardium, named C. edentulum by some authors; C. Greenlandicum by others: fig. 123*.

ACASTA. Leach. _Order_, Sessile Cirripedes, _Lamarck_. BALANUS _Montagui_, Sowerby. A small genus separated from Balanus, on account of the cup-shaped base, but re-united by Sowerby, who shews, in his Genera of Shells, that this is a merely accidental circumstance, resulting from the situations in which the shells acquire their growth. If, for instance, the Balanus be attached to a flat surface, in an open situation, the base will be short and flat; if it be placed in a hollow among other growing substances, it will be lengthened out in order that the aperture of the shell may be even with the outer surface of the surrounding mass; and if, as in the Acastæ, it be imbedded in a soft and loose substance, the base, being left to itself, will take a regular form. The Acastæ are found imbedded in sponges. _Ex._ Balanus Montagui, of Great Britain, fig. 26. Also found in the Pacific ocean and Philippines.

ACAVUS. Montfort. _Fam._ Limacinea, Blainville; Colimacea, Lamarck. A division of the genus Helix, which may be considered synonymous with De Ferrusac's sub-genus Helicogena. De Montfort has given H. Hæmastoma, as an example. Fig. 267.

ACCESSARY VALVES, are the smaller or less important testaceous plates, found on the hinge or dorsal margins of the true valves of some shells. Example, the small plates on the hinge of Pholas, fig. 55, a. The Pholades were placed by Linnæus and Bruguière among multivalve shells.

ACEPHALOPHORA. Blainville. (_a_, without; [Greek: kephale], head.) The third class of the type Malacozoaria, Bl. including all bivalve shells, the animals of which have no distinct head. This class corresponds with the Conchifera of Lamarck, and is divided into the orders Palliobranchiata, Rudistes, Lamellibranchiata, and Heterobranchiata, the last of which contains no genera of testaceous Mollusca.

ACHATINA, Auctorum. _Fam._ Colimacea, Lam. (from Achates, an agate.) _Fam._ Limacineæ, Bl. _Gen._ POLYPHEMUS, Montf.--_Descr._ Shell oval or oblong, sub-turrited, light, thin; aperture oval, or pyriform; outer lip sharp; columella smooth, tortuous, truncated, so as to form a notch at its union with the outer lip.--_Obs._ It is from this notch that we are enabled to distinguish Achatinæ from Bulini, which, moreover, generally have a reflected outer lip. The Polyphemi of Montfort have an undulation in the centre of the outer lip. Achatina Virginea, fig. 286. Polyphemus Glans, fig. 288. These land shells are found in various parts of the globe, but attain the greatest size and richness of colouring in tropical climates; particularly in the West India Islands.

ACHATINELLA. SOW. A small group of shells, differing from Achatina in having the inner edge of the outer lip thickened, and a slight groove near the suture of the spire. Fig. 287. Sandwich Islands.

ACHELOIS. Montf. CONILITES Achelois. Knorr. Supp. T. 4, fig. 1.

ACICULA. Nilson. ACHATINA Acicula, Auct. CIONELLA, Jeffreys.

ACIONA. Leach. A genus described by De Blainville as consisting of those species of Scalaria, the whorls of which do not touch each other. If this account be correct, the genus proposed by Leach will include the typical species of Scalaria, such as S. pretiosa.

ACME. Hartmann. A genus formed of TURBO fuscus, Walker. AURICULA lineata, Drap. thus described--"Shell sub-cylindrical, with a blunt tip; mouth ovate, simple, thin, slightly reflected over the pillar, forming a slight perforation." The animal is said to resemble a Cyclostoma, but has no operculum. Auricula lineata, Drap. Hist. 57, t. 3, fig. 20, 21. Southern Europe.

ACTEON. Montf. TORNATELLA, Lam.

ACTINOCAMAX. Stokes. A genus of Belemnitiform Fossils.

ACULEATED. Beset with sharp spines, as the margin of Chiton aculeatus, fig. 227.

ACUMINATED. Terminating in a point, as the apex of Melania subulata, fig. 313.

ACUS. Humphrey. TEREBRA of Lamarck.

ACUTE. Sharp, pointed, or sharp-edged.

ADDUCTOR MUSCLE. That which draws the two valves of a shell together, and leaves a mark on the inner surface of each, called the MUSCULAR IMPRESSION.

ADELOSINA. D'Orb. A genus of microscopic Foraminifera.

ADESMACEA. Bl. (_a_, without; [Greek: Desma], _desma_, ligament.) The 10th family of the order _Lamellibranchiata_, Bl. composed of Mollusca which either bore tubular dwellings in rocks, wood, &c. or live in testaceous tubes, their shells being consequently destitute of the hinge ligament. The action of opening and shutting the valves being limited to the narrow space to which they are confined, or else the valves themselves being soldered into the tube, renders it unnecessary for them to have a ligament to keep them in their places. The genera Pholas, Teredina, Fistulana, and Septaria, belong to this family, which corresponds in part with the families Tubicolaria and Pholadaria, of Lamarck.

ADNA. Leach. One of the genera separated by Leach from _Pyrgoma_, and characterized as consisting of an upper valve, supported on a funnel-shaped base, which is not buried in the coral to which it is attached, like Pyrgoma, but is seen externally. The operculum consists of four valves. Adna, fig. 32. British Channel and Mediterranean.

ADNATE. A term applied by some authors to those shells belonging to the family of Unionidæ, which have the valves joined together at the dorsal margin, not like other bivalves, by a distinct ligament, but by the substance of the shell itself, the valves appearing to grow together in such a manner that they cannot be separated without one of them being broken as will be seen in our figure of Dipsas plicatus, fig. 142. This circumstance has been made the foundation of specific and even generic distinctions, for which however it is insufficient, because many species which when young are "_adnate_," when fully grown have their valves joined together only by a ligament.

ÆGLIA. Say. A division of "Unionidæ," described as having the "shell cuneate; bosses prominent; cardinal teeth much compressed, placed on one side of the bosses. Æglia ovata, _Say_. Occidens _Lea_. Am. Tr. iii. pl. 10." Lardner's Encyclopedia of Malacology.

AGANIDES. Montf. ORBULITES, Lam.

AGATHIRSES. Montf. SILIQUARIA, Auct.

AGINA ----? Belongs to SAXICAVA, Auct.

AKERA. Bl. The fourth family of the order Monopleurobranchiata, Bl. containing the genera Bulla, Bullæa and Bellerophon, which, excepting the last, constitutes the family Bullæana, Lam.

AKERA. A genus of extremely light, horny shells, resembling BULLA, from which it differs, in the outer lip being separated from the body whorl, which is elastic. _Ex._ Bulla fragilis, fig. 247.

ALÆA. Jeffrey's. A genus of minute land shells, resembling _Vertigo_, but separated because they are dextral, while Vertigo is sinistral. _Ex._ fig. 292. A. marginata, Pupa marginata, Drap. found in marshy ground, roots of trees, moss, &c. Britain and Southern and Central Europe.

ALASMODON. Say. A division of the genus UNIO, Auct. consisting of those species which have cardinal, but no lateral teeth. _Ex._ A. complanatus, fig. 141. North America and Europe.

ALATÆ. Lam. A family of the order Trachelipoda, Lam. containing the following genera which may be thus distinguished.

1. ROSTELLARIA. Sinus close to the canal; including _Hippochrenes_, and _Aporrhais_, Fig. 402 to 404.

2. STROMBUS. Sinus not close to the canal. Fig. 406.

3. PTEROCERAS. Same, digitated. Fig. 405.

ALATED. (From Ala, a wing.) Winged, a term applied to shells, when any portion of them is spread out in any direction, as in fig. 403. Hippochrenes, Montf. and fig. 147, Unio Alatus.

ALCADIA. Gray? (B. M. Syn. p. 134) Helicinæ which have a notch in the aperture. A distinction which it is impossible to maintain. See HELICINA.

ALATUS. Humphrey. STROMBUS, Auct.

ALECTRION. Montf. BUCCINUM Papillosum, Auct. fig. 422.

ALEPAS. Rang. A genus of Pedunculated Cirripedes without a shell.

ALVEOLINA. D'Orbigny. A genus of microscopic Foraminifera.

AMALTHUS. Montf. A. margaritaceus, Montf. is a species of AMMONITES described as very flat, keeled, with an angular aperture. It belongs to the family Ammonacea, Lam.

AMARULA ----? A genus composed of MELANIA Amarula, Auct. and similar species.

AMBIGUÆ. Lam. The fourth section of the order Conchifera Dimyaria, containing the family Chamacea, fig. 153 to 155.

AMICULA. A genus formed for the reception of CHITON amiculatus, Auct. the valves of which are covered by an integument; so as to be completely hidden externally.

AMIMONUS. Montf. CONILITES ungulatus, Knorr. A species distinguished only by being slightly curved; _Fam._ Orthocerata, Lam.

AMMONACEA. Bl. The fourth family of the order Polythalamia, Bl. or chambered shells, described as thin, chambered, discoidal, convolute, symmetrical, generally compressed, with visible whorls. This last character is used in De Blainville's System to distinguish the Ammonacea from the Nautilacea. This family contains the genera Discorbites, Scaphites, Ammonites, and Simplegas.

AMMONACEA. Lam. The seventh family of Polythalamous Cephalopoda, Lam. containing the genera Ammonites, Orbulites, Ammonoceras, Turrilites and Baculites, to which may be added Amalthus, Simplegas, Ellipsolites, Nautellipsites, Hamites, Icthyosarcolites, and other genera mentioned in the list of figures 477 to 484.

AMMONITES. Auct. (from Jupiter Ammon.) _Fam._ Ammonacea, Lam. and Bl.--_Descr._ Symmetrical, convolute, discoidal, orbicular; chambers numerous, divided by lobated, branched or sinuous septa, perforated by a Siphon; aperture generally more or less modified by the last whorl. The fossils of the secondary strata which compose this genus are numerous and well known; they are vulgarly termed "snake-stones," and some of them are extremely beautiful, particularly when the internal structure is exhibited by a section. There is some difficulty in distinguishing them from the Fossil Nautili, for although the whorls, being visible and the Septa _sinuous_, may be taken as the characteristics of the Ammonites, yet there are several species which partake the characters of both. The Orbulites of Lamarck (fig. 479) for instance, have sinuous septa like Ammonites, but the last whorl covers those which precede it as in Nautilus. Simplegas Montf. and Bl. (fig. 475) has the whorls visible externally and the septa simple. Ammonites is figured in the plates (478).

AMMONOCERAS, or AMMONOCERATITES. Lam. (from _Ammon_ & [Greek: Keras], ceras, horn.) The shells described under this Lamarckian genus present an anomaly which is considered by Mr. G. B. Sowerby, sen., as merely accidental. They resemble the Ammonites in internal structure, but instead of being spirally convolute they are merely curved like a horn. _Ex._ fig. 477, copied from De Blainville.

AMNICOLA. The name of a genus mentioned in the family of Melaniana in the conchological part of the Synopsis of the British Museum, but unexplained.

AMPHIBOLA ----? The same as AMPULLARIA, Auct.

AMPHIBULIMA. Lam. SUCCINEA Patula, Auct. (fig. 266.) was first published in the Ann. du. Mus. D'Hist. Nat. under the name Amphibulima cucullata. The generic name was afterwards abandoned by its author, and the species stands in his system as Succinea cucullata. West Indies.

AMPHIDESMA. Lam. (from [Greek: Amphô], _ampho_, _ambo_, [Greek: Desmos], _desmos_, _ligamentum_). _Fam._ Mactracea, Lam.--_Descr._ Equivalve, oval or rounded, sub-equilateral, sometimes rather gaping at the sides, with slight posterior fold; hinge with one or two cardinal teeth in each valve, and two elongated lateral teeth, distinct in one valve, nearly obsolete in the other; ligament short, separated from the cartilage, which is elongated and couched obliquely in an excavation of the hinge.--_Obs._ In most bivalve shells, the cartilage and ligament are united in one mass, or placed close to each other; the contrary in this case gives rise to the name, which signifies _double ligament_. This circumstance distinguishes the genus Amphidesma from Tellina, which in other respects it greatly resembles. From Lutraria it may be known by its distinct lateral teeth, and also by its valves being nearly close all round, while the Lutrariæ gape anteriorly. The species do not appear to be numerous, no fossil species are known. A. _Reticulatum_, fig. 85. West India Islands, Brazil, Coast of Pacific, &c.

AMPHIPEPLEA. Nilson. The type of this proposed genus is LIMNEA glutinosa, Auct. Gray's edition of Turton, page 243, plate 9. fig. 103. The shell is polished and the inner lip expanded.

AMPHISTEGINA. D'Orb. A genus of microscopic Foraminifera.

AMPLEXUS. J. Sowerby. A. _Corralloides_, fig. 463. A singularly formed fossil, described as nearly cylindrical, divided into chambers by numerous transverse septa, which embrace each other with reflected margins. It occurs in the Dublin limestone, and resembles a coral or madrepore.

AMPLEXUS. A generic name proposed by Captain Brown for HELIX pulchella, Drap. 112, tab. 107-134. Zurama, Leach.

AMPULLARIA. Auct. (_Ampulla_, a rounded vessel). _Fam._ "Peristomiens," Lam. Ellipsostomata, Bl.--_Descr._ Spiral, globular, sometimes discoidal, frequently umbilicated, covered with a rounded, horny epidermis; spire short; whorls rapidly enlarging; aperture elliptical, rounded anteriorly; peristome nearly or quite entire, thickened and slightly reflected; operculum, testaceous, annular, with a subcentral nucleus.--_Obs._ This genus of fresh-water shells of which a few fossil species occur, is easily distinguished from other genera, by obvious characters, particularly by a thick, horny, greenish-brown epidermis, and the rotundity in form. One species, the A. Cornu-arietis which forms the type of Lamarck's genus Planorbis, requires notice on account of its flatness, but may be known by the aperture which in the Ampullaria is longer than wide, and in Planorbis the contrary. Lanistes, Montf. is described from a _reversed_ species of Ampullaria. The Ampullaria is vulgarly called the Idol Shell, and is said to be held in great veneration by the South American Savages. The animal has a large bag, opening beneath, placed on the side of the respiratory cavity. It is supposed that the animal has the power of filling this bag with water, and that it is thus enabled to live a long time out of water. They have been brought as far as from Egypt to Paris alive, packed in saw-dust. _Ex._ fig. 318. East and West Indies, North Africa, South America, &c.

AMPULLARINA ----? A genus formed for the reception of AMPULLARIA avellana. Fig. 538. From Australia.

AMPULLINA ----? Part of the genus HELICINA, Auct.

ANALOGOUS. A term applied to certain species of fossil shells, which present a certain degree of resemblance to recent species; but which are not sufficiently similar to warrant the use of the term 'identical,' or any other implying that they are of the same species.

ANASTOMA or ANOSTOMA. Fischer. (from [Greek: Ana], _ana_, backwards; [Greek: Stoma], _stoma_, mouth) _Fam._ Colimacea, Lamark. A genus of land shells so named from the singular circumstance of the last whorl taking a sudden turn and reflecting the aperture upwards, so as to present it on the same plane with the spire; so that the animal walks with the spire of the shell downwards resting on the foot. In other respects, the two species of which this genus is composed, resemble other Helices; and belong to De Ferrusac's division "Helicodonta." _Tomogerus_ is De Montfort's name for this genus. _A. depressum_ is represented in the plates figs. 271, 272. The nearest approach to this genus will be found in the fossil shell named Strophostoma, by Deshayes, which, however, has no teeth in the aperture and is provided with an operculum like Cyclostoma. South America.

ANATIFER. Brug. ANATIFA, Lam. This name, which signifies Duckbearing, has been given to the shells commonly called Barnacles, on account of an absurd notion entertained among the ancients, that they inclose the young of the Barnacle duck, in an embryo state. The beautiful bunch of jointed arms, the ciliæ of which serve the purpose of agitating the water, so as to draw in food by the current, were supposed to be the feathers of the future bird. For a description of these shells, see PENTELASMIS; and fig. 34.

ANATINA. Lam. (_That which belongs to a duck._) _Fam._ Myaria, Lam. Pyloridea, Bl.--_Descr._ Thin, transparent, generally equivalve, inequilateral, transverse, marine; hinge with a spoon-shaped process in each valve, containing the cartilage.--_Obs._ Some species included in the genus Anatina of authors, A. striata, for instance, have not the spoon-shaped prominence, but in its place a small, testaceous, moving appendage, connected with the interior of the hinge. These are now separated, and form the genus LYONSIA. The genus Næara, Gray, is composed of Anatina longirostrum, and similar species, which have neither the bony appendage nor the spoon-shaped prominence. Mya is distinguished from Anatina, by the thickness of the shell, and also by having the prominence only in the hinge of one valve. Fig. 69. A. rostrata. The Anatinæ are found in the East Indies and South Sea Islands.

ANATINELLA. G. B. Sowerby. (Dimunition of _Anatina_). A genus so named from its resemblance to Anatina, from which it differs in being destitute of the internal appendage, and having no sinus in the palleal impression. One species having been brought from Ceylon, received the name of Anatinella Sibbaldii. Another has lately been found in the Philippine Islands. Fig. 70.

ANATOMUS. Montf. Tom. 2, plate 279. A microscopic shell, appearing from the figure to resemble SCISSURELLA.

ANAULAX. Brogn. ANCILLARIA, Auct.

ANCILLA. Lam. ANCILLARIA, Auct.

ANCILLARIA. Auct. ANCILLA, Lam. (_A handmaid._) _Fam._ convolutæ, Lam. Angyostomata, Bl.--_Descr._ Smooth, oblong, subcylindrical. Spire short, sutures hidden by enamel. Aperture long, anteriorly emarginated and somewhat effuse. Columella tortuous, oblique, tumid, truncated.--_Obs._ The Ancillariæ are pretty shining shells, enveloped almost entirely by the soft parts of the animal. They resemble Oliva, from which they are distinguished by the suture of the spire being filled up with shelly enamel, nearly covering the surface. The whorls in Oliva being separated by a distinct canal. Ancillaria may be known from Terebellum by the tumid varix at the base of the columella. The well known Ivory shell, Eburna glabrata, _Lam._ belongs to this genus, of which a few fossil species are found in the London clay, Calcaire grossièr and green sand, Turin. The recent species are found in the Islands of the Indian Ocean and Australian Seas. A. glabrata is represented in the plates fig. 455; A. cinnamonea, fig. 456.

ANCULOSA. Say. _Fam._ Melaniana, Lam. Ellipsostomata, Bl. A genus proposed to include some fresh-water shells resembling those of the genus Melania, the difference between them being that the spire of Anculosa is more depressed, and the anterior of the outer lip more angulated than in Melania. On an examination of the different species, however, it will be found that this is quite unsatisfactory, as a generic distinction; because some of the species with short flattened spires, have rounded, and others angulated apertures. North America. An example of each is represented, fig. 314.

ANCYLUS. Geoffroy. _Fam._ Calyptracea, Lam. Otides, Bl.--_Descr._ Thin, obliquely conical, patelliform; apex acute, turned sidewise and backwards; aperture oval; margin simple.--_Obs._ Although the little fresh-water shells described under this name, resemble those of the genus Patella, the animals which produce them are nearly allied to the Lymneanæ. And, it may also be observed, that the shells themselves differ from Patella in not being quite symmetrical, having the apex turned on one side. A. fluviatilis, fig. 246. Found in Great Britain, and in Southern and Central Europe, West Indies, &c.

ANDROMEDES. Montf. VORTICIALIS, Lam. _Fam._ Nautilacea, Lam. A genus of microscopic Foraminifera.

ANGULATED. (Angulatus.) Having an angle, or corner, as the anterior of the aperture of Eulima, fig. 348; the posterior side of Castalia, fig. 140; the whorls of Carocolla, fig. 277.

ANGULITES. Montf. A genus composed of species of fossil NAUTILI, described by De Blainville as not umbilicated, with a dorsal keel and angular aperture. NAUTILUS triangularis Buffon.

ANGIOSTOMATA. Bl. The third family of Siphonobranchiata, Bl. described as differing little from the family of Entomostomata, but having long, narrow, straight apertures, and the columellar lips straight or nearly so. Were it not for the admission of the genus Strombus into this family, it would correspond with COLUMELLARIA and CONVOLUTÆ of Lamarck.

ANNELIDES. The ninth class of invertebrated animals, divided into three orders, namely, A. Apodes, A. Antennés, and A. Sedentaires. The last only contains families of testaceous Mollusca. The animals are vermicular, some naked, others inhabiting shelly tubes. See SEDENTARY ANNELIDES.

ANNULAR OPERCULUM is one which has the nucleus central, or nearly so, the other layers surrounding it in flattened rings. The term concentric is also applied. See Introduction.

ANNULATED. (Annus, a ring.) Composed of, or surrounded by rings, as in the case of Tubicinella, fig. 14.

ANODON. Brug. _Fam._ Submytilacea, Bl. Nayades, Lam. A genus composed of such species of NAYADES as are destitute of teeth on the hinge. Europe, North America, &c. An example is given in A. Cataractus, fig. 152.

ANOMALINA. D'Orb. A genus of microscopic Foraminifera.