Front matter (continued 2)

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 & Κερας, 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 Αμφω, ampho, ambo, Δεσμος, 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 Ανα, ana, backwards; Στομα, 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.

ANOMIA. Fam. Ostracea, Lam. and Bl.—Descr. Irregular, inequivalve, sub-equilateral, foliaceous, pearly within; adhering to marine substances by means of a bony appendage, which passes through a large circular opening in the lower valve; muscular impression divided into three irregular portions; hinge destitute of teeth with a short cartilage.—Obs. The Linnæan genus included not only the shells to which the description above given would apply, but also many other genera, such as Crania, Orbicula, Terebratula, &c. which belong to the Brachiopoda, and are perfectly distinct. The Anomiæ are found in Europe, N. America, Moluccas, Philippine Islands, &c. Fig. 186, in the plates, is a somewhat reduced representation of a full grown specimen of A. Ephippium. Fig. 187, the hinge of the under valve, with the bony process. Fig. 188, the hinge showing the opening through which it passes.

ANOSTOMA. See Anastoma.

ANSATES. Klein. A genus formed of those species of Patella which have a produced, recurved beak. Helcion, Montf. Ex. Patella pellucida, fig. 230.

ANSULUS or ANSYLUS. Mr. Gray conjectures that the name of the genus Ancylus, should be so written.

ANTENOR. Montf. A genus of microscopic Foraminifera.

ANTERIOR. In Bivalves is the side on which the head, or part analogous to the head of the animal lies; it is known in the shell by the umbones, which if turned at all, are turned towards that part. If there be a sinus in the impression of the mantle, it is always on the posterior part of the shell. If the ligament be placed only on one side of the umbones, it is only on the posterior side. The anterior of a spiral univalve is that part of the outer lip which is at the greatest distance from the apex. Of a symmetrical conical univalve such as Patella, it is that part where the head of the animal lies, indicated by the interruption of the muscular impression. Of cirripedes, that part where the ciliæ protrude are anterior; of Brachiopoda, that part which is farthest from the umbones and which corresponds with the ventral margin in other Bivalves. The anterior of symmetrical, convolute univalves, is the outer or dorsal part of the aperture, or that part which is farthest from the spire. Lamarck and other Conchological writers have occasioned much confusion by their errors on this subject; describing the same part of a shell at one time anterior, at another posterior; but generally the reverse of the above arrangement, which is founded upon the natural position of the animal, and generally adopted. The anterior will be indicated by the letter a, in figs. 119, 421, 229, 34, 202.

ANTIGONA. Schum. A genus composed of Venus cancellata, Lam. (fig. 119.) and similar species.

ANTIQUATED. This word, signifying out of date, is occasionally used to express that species of composition which constantly occurs in shells, by each fresh deposit or layer of calcareous matter, forming a new margin, which being replaced by its successor, is no longer used as the margin, and is consequently said to be out of date.

APEX. This term does not apply to the natural position of a shell, but is used in a mathematical sense, to indicate the nucleus or first formed part; which may be considered as the point of the spiral cone. From this point, the shell enlarging rapidly or slowly as it descends, takes a spiral, arched, straight, oblique, convolute, or irregularly spiral course. The apex will be indicated by the letter a, in fig. 282 and 466.

APERTURE or MOUTH. The entrance to the spiral cavity of univalve shells. The parts of the aperture are separately described, as follows: The inner lip or labium is that part which lies over the preceding whorl of the shell. It terminates anteriorly, or towards the lower part in what is termed the columella, so called because it forms a kind of axis on which the volutions turn. The outer lip, sometimes called the labrum, is on the opposite side, or the farthest from the axis. If the edges of the inner and outer lips unite all round, they are described as composing the peritrême. In fig. 318, the aperture is marked by the letter a.

APHRODITA. Lea. (from Αφροδιτη, Greek name of Venus.) A genus composed of Cardium Groenlandicum, Auct. fig. 123*, and other similar species of Cardium, the teeth of which are either wholly wanting, or very indistinct. Northern Ocean.

APICIAL. Belonging to the apex. The apicial extremity of the aperture of a univalve shell, is that which is nearest to the apex of the spire.

APICULUM. Humph. Trochus, Lam.

APLEUROTIS. Rafinesque. A genus unfigured and imperfectly described as differing in some respects from Terebratula and other Brachiopodæ.

APLEXUS. Fleming. A genus composed of Physa Hypnorum, Drap. &c. and described as having the inner lip simple, and not spread over the body whorl.

APLODON. Rafinesque. A genus proposed to be established at the expense of the genus Helix, but upon what grounds does not appear from the imperfect description which is unaccompanied by a figure.

APLUSTRE. Schum. A genus formed for the reception of those species of Bulla which have the spire uncovered. Ex. Bulla Aplustre, (aplustre, a flag.) Auct. fig. 289.

APLYSIA. Linn. (a, without; Πλυω, to wash.) Fam. Laplysiens, Lam. Aplysiana, Bl.—Descr. Horny, transparent, clypeiform, or shield-shaped, placed horizontally on the back of the animal, with its convex side uppermost; apex slightly incurved.—Obs. The animal producing this shell has derived its name from the purplish liquor which it exudes, when disturbed. In contour, it has been fancied to present a certain likeness to a hare crouching, and on this account was called Lepus marinus, or sea hare, by the ancients. The shell bears a strong resemblance to Dolabella, which, however, is much thicker, and more testaceous. The species are found in the Mediterranean, European, and West Indian Seas. A. Petersoni, fig. 254.

APLYSIACEA. Bl. The second family of the order Monopleurobranchiata, Bl. The animals composing this family are either destitute of shells, or are provided with internal ones, which are flat, open, oblique, with the apex or nucleus slightly incurved, not distinctly spiral. This family contains the genera, Aplysia and Dolabella. The first sub-spiral, with the apex terminal; shell thin, horny. Fig. 254. The second the same, but thick and shelly. Fig. 255.

APOLLON. Montf. Ranella Ranina, Auct. Placed by De Blainville in that division of Ranella, which is characterized as being umbilicated. Fig. 393.

APOROBRANCHIATA. Bl. The first order of the second section of Paracephalophora Monoica, Bl. The Thecosmata is the only family of this order containing any approach to shells, these are Hyalæa and Cymbulia.

APORRHAIS. Petiver. A genus formed of Rostellaria Pes-pelicani, Auct. (fig. 404) and similar species. Although the shell presents no characters to distinguish it generically from Rostellaria, those who have examined the soft parts are convinced that it is distinct. Of the three species now known and figured in part I. of Thesaurus Conchyliorum, by the Author, one is common on our own coast, and in the Mediterranean; also North America. See Rostellaria.

AQUATIC. A term applied by some authors to those species of Molluscous animals, which inhabit fresh water, either in rivers, or salt water standing pools, as distinguished from the marine or Mollusca. See Fresh-water.

AQUILLUS. Montf. Triton Lampas, Cutaceus, &c. Auct. Placed by De Blainville in the division of the genus Triton, which is described as having a short spire, being covered with tubercles and umbilicated. Triton Cutaceus, fig. 399.

ARCA. Auct. (Anglicè, a boat.) Fam. Arcacea, Lam.—Descr. Obliquely transverse, subquadrate, equivalve, or nearly so, inequilateral, thick, ventricose, longitudinally ribbed, dentated near the inner margins; hinge rectilinear, forming a flat, external area, upon which the ligament is spread in cross rows, and having a series of small, regular teeth, extending on both sides of the umbones in each valve; muscular impressions distant.—Obs. The shells composing this genus are easily distinguished from those of all other bivalve shells, by the straight, linear row of small, notched teeth, and by the area between the umbones. The genus Cucullæa makes the nearest approach to it in this respect, but it may easily be known from it by the outermost teeth on each side of the row being oblique, and lengthened out; and also by the prominent edge of the muscular impression. These shells are found recent, in various marine localities; fossil, in the tertiary deposits. The Arca Noæ, formerly regarded as the type of this genus, has, with several other species, been separated from it under the name of Bysso-arca, by Swainson, on account of an hiatus in the ventral margin, to admit the passage of a byssus; this is not found in the true Arcæ. The true Arcæ are mostly tropical. Arca Antiquata, fig. 131. Bysso-arca Noæ, 132.

ARCACEA. Lam. A family of the order Conchifera Dimyaria, characterized by a series of teeth placed on the hinge in a line. The genera may be distinguished as follows,

1. Arca. Hinge straight; valves close. Fig. 131.

2. Bysso-arca. Valves gaping. Fig. 132.

3. Cucullæa. Distant teeth oblique; posterior muscular impression prominent. Fig. 133.

4. Pectunculus. Hinge curved. Fig. 134.

5. Nucula. The same, with a pit in the centre of the hinge, including Myopara and Crenella. Figs. 135 to 137.

6. Solenella. Fresh water, oval; a series of teeth on one side of the hinge, only two or three on the other. Fig. 138.

ARCHAIAS. Montf. A genus of microscopic Foraminifera.

ARCHONTE. Montf. Hyalæa, Auct.

ARCINELLA. Schum. Chama Arcinella, Auct.

ARCTICA. Schum. Cyprina Icelandica, Auct.

ARCUATED. (Arcus, an arch.) Bent in the form of an arch, as Dentalium, fig. 2.

AREA. A flat space or disc, on any part of a shell. As for instance, the triangular space on the hinge of Arca, fig. 132, and Spondylus.

ARENACEOUS. (Arena, sand.) Of a sandy texture, as the sand tubes surrounding the bodies of some of the Annellides, named Arenaria on this account. But the word is more commonly used to intimate the habits of the animal, burrowing with its shell in the sand.

ARETHUSA. Montf. A genus of microscopic Foraminifera.

ARGONAUTA. Auct. Commonly called the "Paper Sailor." Fam. Pteropoda, Bl. Order Cephalopoda Monothalamia, Lam.—Descr. Light, thin, transparent or nearly so, symmetrically convolute, carinated by a double row of tubercles, terminating smooth or tuberculated ribs radiating towards the centre; aperture large, elongated; peritrême acute, interrupted by the body whorl.—Obs. The exquisitely beautiful, light and delicate fabrics included under the above name are inhabited by a molluscous animal named the Ocythöe, which is provided with tuberculated arms. These, hanging over the sides of the aperture, give to the whole the appearance of a vessel propelled by oars: a poetical illusion further heightened by the broad, flat membranes of the two arms, which, when vertically expanded, present an idea of sails. Pliny has described the Nautilus (the name has been changed by the moderns) as sailing gracefully on the Mediterranean waters; and Pope has versified the idea in the well known lines

"Learn of the little Nautilus to sail, Spread the thin oar and catch the driving gale."

Scientific men have long been engaged in the interesting discussion, whether the animal really belongs to the shell in which it is found, or whether, having destroyed the rightful owner, it has possessed itself of the "frail bark." It is now, however, proved beyond the shadow of a doubt that the Argonaut is the testaceous part of the Ocythöe, and that the broad membranes which in some representations have been artificially placed as sails, are naturally bent backwards over the shell like the mantle of some other molluscs. The interesting experiments of Madame Power, in the Mediterranean, have contributed very materially to lead the investigations of Naturalists to a satisfactory conclusion. This lady kept a cage under water, in which Argonautæ were bred in great numbers, giving her an opportunity of tracing the gradual development of the shell in all its stages, from the elastic and transparent nucleus to the full grown "Paper Sailor." Fig. 485.

ARIANTA. Leach. A sub-genus of land shells, containing Helix arbustorum, Auct. (Gray, Turton, p. 137.)

ARION. A genus of slugs which have no shells.

ARROW-HEADS. One of the names by which fossils of the genus Belemnites were formerly known.

ARTEMIS. A genus of bivalve shells, distinguished from those of the genus Venus, by having a rounded, denticular form, and a deep, angular sinus in the palleal impression. This does not appear to me to be a sufficient ground of generic distinction, the palleal impressions of the Veneres being subject to great variations. British, also from West Indies, South America, Australia, &c. A. lincta, fig. 118.

ARTICULATED. (Jointed.) Applied to distinct parts of shells, which are fitted or jointed into each other, as the valves of Chitones and those of Balani. The operculum of Nerita is said to be articulated to the columella, having a small process by which it is as it were locked under the edge. See Introduction. The word is also applied to the Cirri, which protrude from the oral openings of Cirripedes.

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

ASIPHONIBRANCHIATA. Bl. The second order of Paracephalophora Dioica, Bl. Consisting of spiral univalves, which have no notch or canal at the anterior part of the aperture. This order is divided into the families Goniosomata, Cricosomata, Ellipsostomata, Hemicyclostomata, and Oxystomata.

ASPERGILLUM. Lam. (From Aspergo, to sprinkle.) Fam. Tubicolæ, Lam. Pyloridea, Bl.—Descr. The small, equal, equilateral valves are cemented into, so as to form part of, a large tube; the umbones are slightly prominent outside. The tube is elongated, rather irregular, granulated with sandy particles, and terminated at the base by a convex disc, which is perforated by small pores, elongated into tubes round the edge, presenting a resemblance to the spout of a watering pot, whence the name is derived. Loc. New Holland, Java, New Zealand, Red Sea. Fig. 44. Aspergillum Vaginiferum.

ASSIMINEA. Leach. Fam. Turbinacea, Lam.—Descr. Inclining to oval, light, thin, covered with a horny epidermis, spire produced into an acute pyramid; whorls slightly angulated in the centre, rounded beneath; aperture elliptical, slightly modified by the last whorl; inner lip planed; outer lip thin; operculum horny, subspiral. Found in brackish water; one species may be procured abundantly on the muddy shores of the Thames, in Kent. There are also species from Calcutta, China, Tahiti, and Australia. Without comparing the animals, it is difficult to distinguish this genus from some species of Littorina. Fig. 363. A. Grayana.

ASTACOLUS. Montf. A genus of microscopic Foraminifera. Cristellaria Crepidula, Lam.

ASTARTE J. Sowerby. (Name of a Sidonian Goddess, Ashtaroth in Scripture.) Fam. Nymphacea, Lam. Genus Crassina, Lam.—Descr. Suborbicular, equivalve, inequilateral, thick, compressed; hinge with two solid diverging teeth in the right valve, one tooth and a slight posterior elevation in the left; muscular impressions, two in each valve, uniform, united by a simple palleal impression; ligament external.—Obs. This genus differs from Venus, Cytheræa, &c. in not having a posterior sinus in the impression of the mantle. The hinge also differs in having but two cardinal teeth. Astarte differs from Crassatella in having no internal cartilage in the hinge. Some of the species are British, others are from America, and one from Sicily. The fossils occur in Crag, Lower Oolite, &c. Fig. 110. A. Danmoniensis.

ASTROLEPAS. Klein. Coronula Testudinaria, Auct. Chelonobia, Leach. Fig. 15.

ATLANTA. Lesueur. Fam. Pteropoda, Lam. and Bl.—Descr. Spiral, convolute, transparent, fragile, compressed, with a broad, fimbriated, dorsal keel, and a narrow aperture. This shell, which is called "corne d'ammon vivant," is found in the Atlantic. The small Pteropod, figured in Sowerby's Genera as Limacina, belongs to this genus. Atlanta Helicialis, fig. 220.

ATRACTODON. Charlesworth. (Mag. Nat. Hist. 2nd series, Vol. 1. p. 218. ) A genus proposed for the admission of a singular fossil shell, found on the beach at Felix-stone, of which the following are the characters;—fusiform, aperture equalling the spire in length, terminating anteriorly in a slightly recurved canal; columellar lip smooth, curved, thickened posteriorly into a blunt tooth; spire obtuse.—Obs. This shell would be a Fusus were it not for the tooth on the posterior extremity of the columellar lip. The only species known is regularly striated in a spiral direction, and named A. Elegans.

ATRYPA, Dalman. A genus of brachiopodous bivalves, distinguished by the valves being nearly equal, and the umbones not separated by an intermediate area. A. reticulata, fig 302.

ATTACHED. Shells are attached to marine substances by various means; in some cases by a byssus, or a bunch of tendinous fibres passing through an opening between the valves, which gape at their margins to admit a free passage, as in the genera Byssoarca and Mytilus. In other cases the byssus is of a more compact substance, and passes through a perforation in the shell itself. This is the case with many of the brachiopodous shells, in some species of which the perforation is in the point of the umbones, a specimen of which is represented in the Introduction. This species of attachment does not keep the animal motionless, although it is confined to a particular spot. Other shells are attached by a portion of their own substance, as in Chama, Spondylus, Serpula, &c. in which instances, the attached valve is motionless, and is termed the under valve. The Pedunculated Cirripedes are attached by a tubular tendinous process, called a peduncle.

ATTENUATED. Drawn out, long, thin, tapering, as the extremities of Ovulum Volva, fig. 442.

ATYS. Montf. A generic name including those species of Bulla, which are described as "convolute, with the last whorl covering the rest and hiding the spire, the apex rounded at both ends." Bulla Naucum, Auct. fig. 250.

AURICLE. (A little ear.) See Auriculated.

AURICULA. Lam. (Dim. from Auris an ear.) Fam. Auriculacea. Bl. Colimacea, Lam.—Descr. Oval or oblong, cylindrical or conical; aperture long, narrow, generally narrowest in the centre; rounded anteriorly, with two or three strong folds on the inner lip, and the outer lip thickened, reflected or denticulated; spire short, obtuse, epidermis horny, brown.—Obs. The above description includes the A. coniformis, f. 298. and several other conical species with narrow apertures which formed the genus Melampus, Montf. and Conovulus, Lam. The latter author suppressed his genus on ascertaining the Conovuli to be land shells. We exclude, however, the A. Dombeyana, Lam. f. 300. and several similar species, which being more rounded, having thin outer lips and but one fold on the columella, are described under the generic name Chilina, Gray. It appears rather doubtful whether the Auriculæ are marine or fluviatile, but the animals appear to be amphibious. The Auriculæ are principally found in Salt Marshes of Tropical climates, some small species are found on the Southern European Coasts, as far north as Britain and south as Tierra del Fuego. The Auriculæ formed a part of the genus Voluta of Linnæus, f. 297. A. Judæ, f. 298. A. Coniformis.

AURICULATED. Some bivalve shells, such as Pecten, fig. 171, 172, have a flat, broad, somewhat triangular appendage on one or both sides of the umbones, called an auricle, or little ear. If on one side only, they are said to be uni-auriculated; if on both, they are said to be bi-auriculated.

AURICULACEA. Bl. The second family of the order Pulmobranchiata, thus described; "shell thick, solid; aperture more or less oval, always large, rounded anteriorly, and contracted by teeth or folds on the columella." This family is included in the genus Voluta of Linnæus, on account of the plaited columellar lip, a character by which that heterogeneous assemblage of shells is distinguished. It forms part of the family of Colimacea, Lam. from which they differ not only in general form, but also in the fact of the animals being partly amphibious, always living (according to De Blainville) on the sea shore, and being occasionally covered with water for a short time. It contains the genera Pedipes, Auricula, Pyramidella.

AURIFERA. Bl. Otion, Auct.

AURIFORM. (From Auris, an ear; forma, shape.) Ex. Haliotis, fig. 338.

AURISCALPIUM. Megerle. Anatina, Lam.

AVICULA. Lam. (From Avis, a bird). Fam. Malleacea, Lam. Margaritacea, Bl.—Descr. Inequivalve, inequilateral, foliaceous, subquadrate, oblique, pearly; hinge rectilinear, lengthened into auricular appendages, with a small indistinct tooth in each valve, an elongated, marginal, ligamentiferous area, and an hiatus in the left valve, for the passage of a byssus; one circular muscular impression, near the centre of each valve, with a series of smaller ones arranged in a line towards the umbones.—Obs. The Meleagrinæ of Lamarck, Margaritiferæ, Schum. included in this description, consist of the more rounded species, and do not present the elegant obliquity of form, nor the wing-like auricles from which the genus Avicula receives its name. The Aviculæ are pearly within. From A. margaritifera, a young specimen of which is figured in the plates, fig. 164, is obtained oriental pearls. This is an example of Meleagrina. A. Hirundo, fig. 163, belongs to the genus Avicula of Lamarck. It is, however, needless to continue the separation. Aviculæ are from E. and W. Indies, Mexico, Coasts of the Pacific, Mediterranean, British Islands, &c. Fossil species occur in the London clay, &c.

AXINUS. J. Sowerby.—Descr. Equivalve, transverse; posterior side very short, rounded, with a long ligament, placed in a furrow, extending along the whole edge; anterior side produced, angulated, truncated, with a flattish lunule near the beaks. The late Mr. James Sowerby, who described this shell in the Mineral Conchology, did not consider his genus as established, not having seen the hinge.

AXIS. The imaginary line, round which the whorls of a spiral shell revolve. The extremities of the axis are pointed out in fig. 379, by the letters, a. a. See "Columella."

AZECA. Leach. Fam. Colimacea, Lam.—Descr. "Animal like Bulinus, with subcylindrical, rather obtuse shell, covered with a polished periostraca (epidermis); aperture pear-shaped, curved and pointed at the top; the margin thick, obtuse, united all round and toothed; the axis imperforated." Gray's edition of Turton's British Shells, page 189.—Obs. The Turbo Tridens of Montagu, upon which this genus is founded, resembles Bulinus lubricus in general form and character. Both these shells differ from the true Bulini in having the peritreme entire, and in being pellucid and glossy. Azeca differs from Bulinus lubricus in having three teeth in the aperture, two on the inner lip and one on the outer. Not seeing the necessity for creating a genus on grounds so slight, I have simply transcribed the description given above, leaving others to form their own conclusions as to the propriety of separating this shell from the genus Bulinus. Britain, Central and Southern Europe. Azeca Tridens, fig. 290.

AZEMUS. Ranzani. Conia, Leach.

BACULITES. Lam. Fam. Orthocerata, Bl. Ammonacea, Lam.—Descr. Straight, conical, tubular, laterally compressed; chambers divided by very sinuous lobed septa, the last elongated; aperture elliptical; siphon dorsal.—Obs. This genus differs from Orthoceras in the same manner in which Ammonites differs from Nautilus, having its septa sinuated and branched. A Baculite might be described as a straight Ammonite. This genus is known only in a fossil state. It is found in the Cretaceous Limestone of Maëstricht and Valognes. Fig. 484. B. Faujasii.

BALANUS. Brug. (an Acorn; "gland de Mer." Fr.) Order Sessile Cirripedes, Lam. Fam. Balanidea, Bl.—Descr. Shell composed of six valves articulated to each other side by side in a circle, by the insertion of lamina; closed at the base by a flat, cylindrical or cup-shaped valve, by which it is generally attached; and at the apex by a conical operculum, consisting of four valves in anterior and posterior pairs. Each valve of the shell is divided into a rough triangular portion pointed towards the apex, and a flat area on each side.—Obs. This description includes the Acasta of Leach, which growing in sponges, has the base cup-shaped; Conoplæa of Say, which being attached to the stems of Gorgonia and sea-weeds has the base elongated and lanceolate, and Chirona, Gray. Balanus is the only genus of Sessile Cirripedes the shells of which consist of six parietal valves, except coronula, which has no shelly base, is flatter, and has the valves of the operculum placed horizontally. The Balani are common in all seas, adhering to rocks, corals, floating timber, and to each other. The fossil species are found in the newest strata, at Bordeaux, Paris, &c. Fig. 25. B. Tintinnabulum; 26. Acasta Montagui; 27. Balanus galeatus, Conoplæa, Say.

BALANIDEA. Bl. The second family of the class Nematopoda, Bl. corresponding with Sessile Cirripedes, Lam., and consisting of Coronular Multivalves, which are fixed, and in a manner soldered to submarine substances, by the base of the shell; as distinguished from the Lepadicea, Bl., Pedunculated Cirripedes, Lam., which are attached by a fleshy stalk. The Balanidea are composed of two sets of valves, besides the shelly plate or base on which they rest. The first, called the Parietal valves, are arranged so as to surround the body of the animal; the second, called the Opercular valves, are placed horizontally, so as to cover the aperture.

BALEA. Gray. Fam. Colimacea, Lam.—Descr. Spiral, turrited, concentrically striated, sinistral, and covered with a thin brown epidermis; spire composed of numerous whorls, gradually increasing in size; aperture small, sub-quadrate; peritrême entire, slightly thickened, with a very slight fold on the columella; axis perforated.—Obs. A genus of small land shells, found in moss at the roots of trees in Britain, not very nearly resembling any other land shells, except Clausilia, from which they differ in not having the clausium. They have been placed in Helix by De Ferrusac, and in Pupa by Draparnaud. B. fragilis, fig. 296. Helix perversa, Fer. Pupa perversa, Drap.

BARBATA. Humphrey. Unio, Lam.

BARNACLES. Pentelasmis, Auct. (fig. 34.) Called Anatifa, by Linnæus and Lamarck, from the ancient notion that they were the eggs or embryo of the Barnacle Duck. See Anatifer.

BASE. In all shells which are attached to sub-marine substances, the base is that part of the shell which forms the point of attachment,—as for instance, the attached valve of Spondylus, the basal plate of Balanus, the lower part of the peduncle of Pentelasmis; in Unattached Bivalves, the margin opposite to the umbones, where the foot of the animal, or the part analogous to it, protrudes; in spiral univalves, the aperture, which rests on the back of the animal when walking. Lamarck and some other authors have used the term base as simply opposed to apex, and apply it to the anterior of the aperture.

BATOLITES. Montf. Hippurites, Auct.

BEAK. The Apices, or points of the valves of a bivalve shell, generally termed Umbones, in descriptions. Also any part which is rostrated or drawn out like a beak.

BEAKED. See Beak and Rostrated.

BEAR'S-PAW-CLAM. The common name for Hippopus maculatus, a representation of which is given in the plates, fig. 156.

BELEMNITES. Auct. (Βελεμνον, belemnon, a dart, or arrow.) Fam. Orthocerata, Bl. and Lam.—Descr. Straight, conical, consisting of two parts; the external portion forming a thick solid sheath, with a cavity at the base to admit the internal portion or nucleus, which is mathematically conical, and is divided into chambers by smooth simple septa perforated by a lateral siphon.—Obs. These singular fossils, which are found in most secondary beds, have long attracted the attention of philosophers as well as of the ignorant, from whom they have received the various appellations of Thunder-Stones, Petrified Arrows, Petrified Fingers, Devil's Fingers, Spectre Candles, &c. The above description is framed to include the genera Hibolithes, Porodragus, Cetocis, Acamas, and Paclites of De Montfort, and Actinocamax, Stokes. Fig. 466 to 468.

BELLEROPHON. Montf. (or Bellerophus).—Descr. Convolute, symmetrical, umbilicated, with a double dorsal ridge; aperture wide, semilunar.—Obs. The fossils composing this genus resemble Nautilus in general appearance, but not being chambered shells they approach very near to Argonauta, from which they differ only in the thickness of their shell and in roundness of their external form. This genus is erroneously placed by De Montfort among chambered shells, and by De Blainville next to Bulla. It belongs to the Monothalamous Cephalopoda of Lamarck. This fossil is found principally in the Carboniferous Limestone. Fig. 486, 487, represent B. tenuifasciata.

BELOPTERA. The bony support of a species of Cuttlefish, partly resembling Sepia.

BIAPHOLIUS. Leach. A genus believed to be identical with Hiatella.

BI-AURICULATED. Having two auricles placed at the sides of the umbones, as in Pecten, fig. 171. See Auriculated.

BICATILLUS. Sw. A sub-genus of "Calyptrædæ," including those species, which have cup-shaped internal septa, as for example, Calyptræa extinctorium, fig. 235.

BICONIA. Sw. A sub-genus of "Calyptrædæ," including those species in which the septum is partly spiral.

BIFID. Divided, double.

BIFRONTIA. Deshayes. Also Omalaxis, Desh. Fam. Turbinacea, Lam.—Descr. Discoidal, planorbicular, with whorls sometimes not contiguous; umbilicus deep, keeled at the margin; aperture subtriangular, somewhat dilated; outer lip acute, separated by a deep notch at both extremities.—Obs. We do not see any reason for separating this genus from Solarium, except the last mentioned character. The few fossil species which this genus contains (Solarium disjunctum, Bifrons, &c.) are found principally in the Paris basin. Fig. 354. Solarium Bifrons.

BI-FURCATE. Double pronged, or having two points. Ex. the internal appendage of Calyptræa Equestris, fig. 234.

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

BILABIATED. Having the edge of the outer lip as it were doubled, by one part of the lip being more thickened and reflected than the other, so as to form a ledge, or second lip.

BILOBATE. Having two prominent parts, as the outer lip of Rostellaria Pes-Peleeani, fig. 404.

BIPARTITE. Composed of or divided into two parts; double; as the valves of Platylepas, fig. 19, each of which has a septiform division in the centre; also the area on the hinge of Spondylus. See Frontispiece.

BIROSTRA. Sw. A genus composed of species of Ovulum, which have elongated extremities, as, for instance, Ovulum Volva, fig. 442.

BIROSTRITES. Lam. (Double Beak.) A fossil formerly considered as a distinct bivalve shell, with conical umbones, and placed in the family of Rudistes by Lamarck, but now known to be an internal cast of Sphærulites, fig. 196.

BISIPHYTES. Described by De Montfort as resembling a Nautilus, but having two distinct siphons. As no such fossil species is now known to Naturalists, it appears probable that De Montfort having a specimen of some Nautilus, with an accidental depression, took it for a second siphon.

BITHINIA. Gray. A genus described as differing from Paludina, in having the operculum shelly, and the mouth of the shell thickened internally. Paludina impura, Auct. Fig. 537.

BITOMUS. Montf. A microscopic shell, deriving this general appellation, from the appearance of a double aperture.

BIVALVE. A shell composed of two equal, or nearly equal principal parts, each part having a separate nucleus, turning upon each other by means of a hinge. The class Conchifera of Lamarck, Acephalophora of De Blainville severally include the whole of the bivalve shells; the latter name being derived from the fact that the animals have not distinct heads, and neither eyes nor tentacula. All bivalve shells are marine or fresh-water. They form the class Dithyra of Aristotle. It may be observed that some of the Acephalophora, the Pholades, for example, have small testaceous pieces fixed on the hinge, which are called accessary valves. These are still fairly bivalve shells, although the genus Pholas has been placed by some writers among the multivalves.

BOAR'S TUSK. A common name given to shells of the genus Dentalium. One particular species has received a specific name in accordance with a supposed resemblance, namely, Dentalium Aprinum, (of a Boar.)

BONELLIA. Desh. A genus formed, in the first instance, for the reception of Bulinus terebellatus, Lam. which Mr. G. B. Sowerby, in his Genera of Shells, united with the genus Pyramidella. M. Deshayes, however, in his new edition of Lamarck, makes the genus Bonellia include several species which I have arranged in the genus Eulima. From the remarks of M. Deshayes, tom. 8, p. 286, 287, we are led to suppose that the estimated difference between Eulima and Bonellia consists in the latter having the axis perforated; or in other words, umbilicated. After remarking "que Mr. Sowerby, junr. confond deux choses bien distinctes, sous le nomme d'Eulima," M. Deshayes gives the following description of his genus, (translated) "shell turriculated, smooth, polished, with the apex acute and laterally inclined; axis perforated throughout its length; aperture small, entire, angular at the extremities; columella simple and without folds; outer lip thin, simple, nearly parallel with the longitudinal axis." That author further remarks, "Mr. Sowerby, junr. à signalé cinque espèces vivant, que nous rapportons à notre genre." (Sowerby, junr. Conchological Illustrations, parts 52 and 53; 50, Great Russell Street, Bloomsbury.) The species thus selected are E. splendidula, E. marmorata, E. interrupta, E. imbricata, E. brunnea; the two last of which have the umbilicus so inconsiderable, as to be scarcely distinguishable from other species, which M. Deshayes has left in the genus Eulima, and which have a slight hollow, almost approaching to a perforation, behind the columella. Eulima marmorata, (Bonellia, Desh.) is figured in the plates, fig. 348.

BODY WHORL. The last whorl, constituting the bulk of the shell.

BORELIS. Montf. Melonia, Bl. A genus of microscopic Foraminifera.

BORER or PIERCER. A term applied to those species of Acephalopodous Mollusca, which bore holes as dwellings in the rocks, as the Pholades, and some others.

BRACHIOPODA. Lam. A family of symmetrical bivalves belonging to the third section of Lamarck's order "Conchifera Monomyaria," described as bivalve (generally symmetrical) adhering to marine bodies, by a tendon passing through the shell, having no true ligament. What most distinguishes this family and renders it remarkable is the structure of the animal. It has two elongated, tendril-shaped arms. When the animal is in a state of repose these arms are coiled up spirally and enclosed in the shell, but when required for use, are unfolded and extended. This family contains the genera Orbicula, Terebratula and Lingula, in the system of Lamarck, to which may be added Thecidium, Productus, Spirifer, Magas, Pentamerus, Crania, Strigocephalus, Strophomena, and some others enumerated in the explanation of figures 201 to 219. The above genera may be thus distinguished.

1. Orbicula. Umbones central; byssus passing through a hole in the flat valve. Fig. 201.

2. Atrypa. Without foramen or space between the valves. Fig. 203.

3. Producta. The same, valves produced, overwrapping; including Leptæna. Fig. 206, 206*.

4. Terebratula. Hinge of the upper valve produced beyond that of the other, with a pit or foramen; including Delthyris, Orthis, Trigonosemus, Magas, Strophomena. Fig. 202, 205, 207, 208, 209.

5. Spirifer. The same, with deep triangular area; spiral folds in the interior; including Trigonotreta and Cyrtia. Fig. 204, 214, 215.

6. Thecidium. Large valve attached; curved ridges in the inner surface; two jutting points or teeth on the hinge. Fig. 216.

7. Crania. Attached by the surface of the valve; muscular impressions four, forming a face. Fig. 197, a, b.

8. Pycnodonta. Irregular; hinge with raised pointed teeth. Fig. 217, 218.

9. Pentamerus. Valves divided by septa; including Gypidia. Fig. 210 to 213.

10. Lingula. Valves equal, gaping, with a peduncle. Fig. 219.

BRACHITOMA. Swainson. A genus composed of Pleurotoma strombiformis and similar species, described as "sub-fusiform; resembling a small Strombus or Fusus; spire and aperture of equal length; canal short; outer lip slightly ascending, and forming a short canal; sinus very small and nearly semicircular; inner lip thickened above. B. Strombiformis, Sow. Man. fig. 381." Europe, East and West Indies, China, &c.

BRANCHIFERA. Bl. The second family of the order Cervicobranchiata, containing the following genera of symmetrical univalves:—Fissurella, Emarginula, and Parmophorus.

BRISMÆUS. Leach. Order. Pedunculated Cirripedes. Lam.—Descr. Seven plates, three pairs lateral, one dorsal; form cylindrically conical; pedicle not described. Hab. Holes in corals. B. Rhophodius, fig. 38.—Obs. This minute shell most nearly resembles Pollicipes Mitellus, fig. 37*, but the difference may be seen at once by comparing the figures.

BRONTES. Montf. This generic name is given to such species of Murex as have a very long, closed canal; with a short spire, circular aperture, and are destitute of spires and ramifications. Brontes (Murex) Haustellum, fig. 390.

BUCARDIA. Schum. Isocardia, Auct.

BUCCINUM. Linn. Fam. Purpurifera, Lam. Entomostomata, Bl.—Descr. Subovate or oblong, covered with an epidermis; spire turrited, consisting of few whorls; aperture wide, subovate, terminating anteriorly in a very short canal, reflected over the back; outer lip simple, slightly reflected; inner lip spread over a portion of the body whorl, terminating in a thick, smooth columella; operculum horny. Hab. British Seas, Northern Ocean, and Coast of Africa. Most of the fossil species occur in Crag, some in upper marine formation and London clay.—Obs. There are considerable difficulties in keeping this genus distinct from others nearly related to it, into which many of the species run by imperceptible gradations. The genus Nassa has been separated on account of the little notch, which terminates the columella. Some species of Terebra come so close upon the Buccina, that it is difficult to say where one genus ends and the other begins. T. Buccinoides, fig. 427. Buccinum Undatum, the common Whelk, fig. 421.

BUFO. Montf. A generic division of the species composing Ranella, characterized as having the shell not umbilicated. Ex. R. ranina, fig. 394. The above character is scarcely sufficient in some cases, even as a specific distinction.

BULBUS. Humph. Rapella, Swainson. A genus formed for the reception of Pyrula papyracea, Auct. (fig. 389), and similar species. Rapanus, Montf.

BULIMIMA. Montf. A genus of microscopic Foraminifera.

BULIMULUS. Leach. Fam. Colimacea, Lam. The author is unacquainted with the characters by which the two or three species included in this genus are to be distinguished from Bulinus. We have represented, fig. 283, Bulimulus trifasciatus, Leach, (Bulinus Guadaloupensis, Auct.) This occurs in the same limestone which encloses the half fossilized human remains from the Grand Terre of Guadaloup. Several species are described by the Rev. L. Guilding in the Zoological Journal, namely, the B. Undulatus, Antiguensis, and Proteus; but neither from the shells themselves, nor from the figures of the animal, can we draw any information as to the generic character; the difference alleged by Mr. Swainson and Mr. Gray being a comparative thinness in the outer lip.

BULINUS. Brug. (Bulinus, Lam.) Fam. Colimacea, Lam. Limacinea, Bl.—Descr. Oval or oblong, light, covered with a thin epidermis; spire obtuse, variable in length and in the number of whorls, which are generally few; aperture wide, oval, rounded anteriorly; outer lip simple, usually reflected, joining the columella without a sinus; inner lip reflected over part of the body-whorl. The Bulini are land shells, found in many parts of the world.—Obs. The genus Bulinus can only be distinguished from Helix by its oval form; it forms part of the genus Helix of De Ferrusac, under the sub-generic designation of Cochlostyla. It is known from Achatina by the absence of the notch at the point of union between the inner and the outer lips. The young are produced from eggs, which are as firm and opaque as those of birds. (See Introduction.) Bulinus rosaceus, fig. 282. B. Guadaloupensis, fig. 283. B. Lionetianus, fig. 284. B. lubricus, fig. 285. Many new species were brought to this country by Mr. Cuming, and are represented in the Conchological Illustrations, published by the Author at 50, Great Russell Street, Bloomsbury, (in parts 21, 22, 23, 26, 27, 30, 31, 34, 35, 137 to 146, 185, 186.) Species occur in Europe, West Indies, Brazil, and South America generally. Some small species are British.

BULLA. Auct. Fam. "Bulléens," Lam. Akera, Bl.—Descr. Generally thin, smooth, oval, oblong or cylindrical, more or less convolute; spire short, depressed, or hidden by the last whorl; aperture long, wide in front, gradually narrowing towards the spire; outer lip thin; inner lip spread over a part of the last whorl.—Obs. The shells composing this genus are very variable in form. The light horny species with an elastic lip is called Akera, fig. 247. The more decidedly convolute species with hidden spires are the Atys, Montf. B. Naucum, fig. 250. B. Lignaria, fig. 251, is Scaphander of Leach. The light, thin species, with extremely wide aperture, fig. 248, is Bullæa aperta, Lam. The genus Bullinula of Dr. Beck, consists of those species which have more produced spines, fig. 253. The Bullæ are marine, and inhabit all climates. The fossil species occur in tertiary beds.

BULLÆA. Lam. Bulla aperta, Auct. fig. 248.

BULLÆANA. ("Bulléens, Lam.") A family belonging to the first section of Lamarck's order, Gasteropoda, containing the genus Bulla. The genera Bullæa, Akera, Aplustra, Atys, Scaphander, Bullinula, into which it has been divided, may all be fairly included under the name Bulla.

BULLIA. Gray. A genus of shells partly resembling Buccinum, and Terebra in general form, being more elongated than the former and more ventricose than the latter. Mr. Gray remarks in the Synopsis of the British Museum, page 114, that the Bulliæ resemble the Nassæ in most characters, "but they have a very large, broad foot, and the hinder part of the inner lip of the shell being extended beyond the mouth, forms a raised enamelled band round the suture of the whorls, as is also the case with the Ancillariæ and some Volutes." Bullia vittata, fig. 427, is an example of the genus. The name Subula is given by De Blainville to the other species of Terebra, so that if both these genera were admitted, the old genus Terebra must be expunged.

BULLINULA. Beck. Species of Bulla, with produced conical spires, fig. 253.

BYSSOARCA. Sw. (Byssus and Arca.) Fam. Arcacea, Lam. A genus of bivalve shells, composed of the Arca Noæ, and several other species, separated from the genus Arca on account of their shells being attached by means of a byssus passing through an hiatus in the ventral margins. B. Noæ, fig. 132. The species occur in Southern Europe, East and West Indies, China; also, on the coasts of Great Britain.

BYSSOMYA. Cuvier. (Byssus and Mya.) De Blainville states that although the shell of this proposed genus resembles Saxicava, the animal is sufficiently different to justify the separation.

BYSSUS. (Βυσσος, byssus, ancient name for linen.) The tendinous fibres by which some Bivalves are as it were anchored or moored to sub-marine substances. A fine example of this is to be seen in the Pinnæ which bear some resemblance to large Muscle Shells and have an hiatus in the margins of the valves through which a bunch of silken fibres passes. In the British Museum there is preserved a pair of gloves which have been woven of these fibres. The Byssus is peculiar to some bivalve shells such as Muscles, Hammer Oysters, Arca Noæ, &c.

CALCAR. Montf. (a spur.) A genus composed of Trochus stellaris, Lam. and other depressed species of Trochus which are characterized by a stellated keel round the angle of the last whorl; but not including T. Imperialis, which is the genus Imperator, Montf. The difference consists in the latter being umbilicated and the former not. T. stellaris, fig. 358.

CALCAREOUS, (calx, lime.) A term applied to a shell or to its operculum which is composed principally of lime or shelly matter, as is usually the case, in distinction from one which is of an horny, membranaceous texture. The greater number of shells are calcareous, but it forms an important point of distinction with regard to the operculum. The only difference between the genera Trochus and Turbo, as at present established, depends upon the calcareous or shelly, and the corneus or horny texture of the operculum.

CALCEOLA. Fam. Rudistes, Lam. and Bl.—Descr. Equilateral, inequivalve, triangular; umbones separated by a large triangular disc in the lower valve; cardinal margin straight, linear, dentated; lower valve large, deep; upper valve flat, semi-orbicular, forming a kind of operculum to the lower.—Obs. This singular shell, known only in a fossil state, in the Palæozöic beds, is placed by Linnæus in the genus Anomia. Lamarck places it among his Rudistes, but Mr. Sowerby in his genera of Shells, states that it should be added to the family of Brachiopoda. Fig. 194, 195. C. Sandalina.

CALLANTICA. Gray. Pollicipes hispidus, Leach.

CALLIA. Gray? A genus described as having a peculiarly polished shell like Pupina, but wanting the notch.

CALLISOSTOMA. Sw. A genus of shells separated from Trochus, and thus described, "Imperforate; spire elevated, acute; aperture broader than high, transversely ovate, hardly sinuated at the base, and slightly oblique; shells always smooth, and often polished." C. zizyphina is mentioned as an example.

CALLIRHOE. Montf. p. 362, vol. 2. Appears to be figured from the nut or inner portion of a large Belemnite.

CALLISCAPHA. Gray? Iridina Nilotica, Sow. Zool. Journ. 1. pl. 2. Separated from Iridina on account of the hinge margin being smooth.

CALLITHEA. Sw. A sub-genus of Mitræ, consisting of those species, which like M. sanguisuga, have the "spire and aperture of nearly equal length; internal channel nearly obsolete; shell with longitudinal linear ribs, crossed by transverse striæ and bands; base contracted." Swainson Mallac. Lard. Cyclop.

CALLOSITY. A term used in general zoology to express those hard horny tumidities formed in the skin of some animals, (such as the Dromedary, for instance) in those parts which are most frequently used. It is not used in this sense by Conchologists, who apply it to those undefined tumidities or bumps which appear on the inner surface and hinge of some bivalve shells, and to the thickening over the umbilicus of Naticæ. Glycimeris, fig. 67. Natica, fig. 327, 328.

CALPURNUS. Montf. Ovulum verrucosum, Auct. Distinguished by the small circular tubercle at the back of each extremity of the shell. Fig. 441.

CALYPTRACEA. Lam. A family belonging to the first section of the order Gasteropoda, Lam., the shells of which are described as always external, covering the animal, and having no operculum. The genera contained in this family may be thus distinguished.

1. Calyptræa. Conical; apex central, septum spiral, cup-shaped, or forked; including Infundibulum. Fig. 234 to 238.

2. Crepidula. Apex terminal; septum flat, reaching half across the aperture. Fig. 239.

3. Capulus. Conical; apex obliquely curved, no septum. Fig. 240.

4. Emarginula. Apex curved backwards; a notch in the anterior margin; including Parmophorus. Fig. 241, 242.

5. Cemoria. A slit near the apex. Fig. 244.

6. Fissurella. A slit upon the apex. Fig. 245.

7. Rimula. A slit near the margin. Fig. 243.

8. Ancylus. Apex curved sidewise. Fig. 246.

CALYPTRACEA. Bl. The second family of the order Scutibranchiata. Bl. thus described: "Shell more or less conical, not spiral, or very slightly so; aperture large and entire." The genera included in this family are Crepidula, Calyptræa, Capulus, Hipponyx, and Notrêma.

CALYPTRÆA. Lam. Fam. Calyptracea, Lam. and Bl.—Descr. Conical, patelliform, irregular, with an internal, lateral, salient plate or septum, varying in form.—Obs. The internal appendage is in some species cup-shaped, in some it juts out of the centre in a double point; in others it is only a small flap; and in others a spiral disc. These last, which are shaped like Trochus, are separated by De Montfort under the appellation Infundibulum; Trochatella, Sw. The Calyptræa may be known from Crepidula by the septum, which in the latter is a flat plate reaching half way across the cavity. Fig. 234, 5, 6.

CAMERINA. Brug. Nummulites, Auct.

CAMILLUS. Montf. A genus founded upon a minute spiral shell, with a triangular aperture, turned over the back of the last whorl. It is figured in Soldani's Testacea Microscopica.

CAMPULOTUS. Guettard. Magilus, Auct.

CANAL. A groove which characterizes some spiral univalves, where the inner and outer lips unite at the front part of the aperture. This canal is drawn out in some shells to a considerable length, in others it is turned abruptly over the back. The family Canaliferæ, Lam. (fig. 372 to 401), are all provided with this canal.

CANALICULATED. Applied generally to any distinct groove or canal.

CANALIFERA. (Canalifères, Lam.) A family belonging to the order Trachelipoda, Lam. nearly corresponding with the family Entomostomata in De Blainville's system, and described as having a canal of greater or less extent at the anterior part of the aperture. This canal is sometimes straight, sometimes tortuous, and in some genera it is recurved over the back of the shell. All the shells have an operculum, and the thickness of the perfectly formed outer lip does not increase with age. The Canalifera are characterized by having a canal, in distinction from the Purpurifera, which have only a notch. This family contains the following genera,

1. Cerithium. Club-shaped. Fig. 372.

2. Potamis. The same, fresh water. Fig. 377.

3. Nerinea. The same, with internal folds. Fig. 374.

4. Triphora. Anterior and posterior canals closed so as to present three openings. Fig. 375, 376.

5. Telescopium. Pyramidal, trochiform. Fig. 378.

6. Pleurotoma. A slit on the upper part of the outer lip; including Clavatula. Fig. 379, 381.

7. Turbinella. Three horizontal folds on the columella. Fig. 382, 383.

8. Spirillus. Spire papillary; one fold on the columella. Fig. 384.

9. Cancellaria. Three folds, and internal costæ. Fig. 385.

10. Fasciolaria. Oblique folds, the lowest the largest. Fig. 386.

11. Fusus. Fusiform; no folds on the columella. Fig. 387.

12. Pyrula. Pear-shaped. Fig. 388 to 390.

13. Struthiolaria. Outer lip thickened; sinuated. Fig. 391.

14. Ranella. Two rows of varices; a canal at each extremity of the aperture. Fig. 393, 394.

15. Murex. Three or more rows of varices; only one distinct canal. Fig. 395, 396.

16. Typhis. A tubular perforation between each varix. Fig. 397.

17. Triton. Varices not in rows. Fig. 398 to 401.

CANCELLARIA. Auct. (From Cancellatus, cross-barred, like window frames or net work.) Fam. Canalifera, Lam. Entomostomata, Bl.—Descr. Oval, thick, cancellated; spire generally short, pointed; aperture sub-ovate, emarginated anteriorly, pointed at the posterior extremity; outer lip marked within by transverse ridges; inner lip spread over part of the body whorl, terminating in a straight, thick, obtuse columella, with several strong oblique folds. Hab. Indian Ocean, Coast of Africa, America, and West Indies. Fossils found in London Clay and Calc-grossier of Paris. Differing from Turbinellus in form and in the transversely ribbed inside of the outer lip. Fig. 315. C. reticulata.—Obs. The latest enumeration of the species of this genus is contained in a catalogue published by Mr. G. B. Sowerby, senior, accompanying the author's figures of the new species, amounting to 38, in parts 9 to 13 of the Conchological Illustrations. The greater part of these new species were brought to this country by Mr. Cuming.

CANCELLATED. (From Cancellatus, cross-barred.) Applied generally to any shells which are marked by ridges crossing each other as Cancellaria, fig. 385.

CANCILLA. Sw. A sub-genus of Mitræ, described as having "the whorls crossed by transverse linear ribs; inner canal wanting, plates very oblique; form slender; outer lip thin." Ex. M. Isabella, M. sulcata.

CANCRIS. Montf. Crepidulina, Bl. A genus of microscopic Foraminifera.

CANOPUS. Montf. A genus of microscopic Foraminifera.

CANTHAPLEURA. Guild. A genus composed of those species of Chiton, which have the mantle rough, with moveable spines, prickles, or hairs. Ex. C. spinosus, fig. 227.

CANTHARIDUS. Montf. Trochus Iris, Auct. and analogous species. Elenchus, Humph.

CANTHARUS. Montf. A genus of microscopic Foraminifera.

CANTHIDOMUS. Sw. A sub-genus of Melanopsis, thus described: "spire generally short; whorls coronated with spines, or marked with longitudinal ribs; base obtuse. C. costata, Sow. Gen. f. 3." Melanopsis costata, plates, fig. 315.

CANTHORBIS. Sw. A sub-genus of the sub-family Trochinæ, Sw. Described as being "nearly disc-shaped: spire but slightly raised; the margin of the body-whorl flattened, and serrated with flat spines; inner lip united to the outer; pillar and aperture as in the last. (Tubicanthus.) C. imperialis. Mart. 173. f. 1714." This sub-genus appears to include those species of which De Montfort's genera Imperator and Calcar are formed.

CANTHROPES. Montf. Described as resembling a Nautilus, with the whorls increasing so gradually, that the dorsal edge of the aperture advances but little beyond the last whorl. This genus is not mentioned by Blainville or Lamarck.

CAPITULUM. Klein. Pollicipes Mitellus, Lam. fig. 37*.

CAPRELLA. ——? Plekocheilus, Guild. Auricula Caprella, Lam.

CAPRINA. D'Orb. Diceras. Auct.?

CAPRINUS. Montf. (Conch. Syst. t. 2. p. 143.) The figure appears to be intended to represent Helix Nux-denticulata.

CAPSA. Brug. Fam. Nymphacea, Lam.—Descr. Equivalve transverse, subequilateral, subtrigonal; cardinal teeth, two in one valve, one notched in the other; lateral teeth remote, obsolete; an external ligament; two muscular impressions in each valve; a large sinus in the muscular impression of the mantle.—Obs. This genus is so nearly related to Donax, that it is difficult to distinguish it at first sight. The Capsæ, however, have not the short, plain, straight, posterior side, the distinct lateral teeth, nor the crenulated margins which characterize nearly all the Donaces. They are found in the British Channel, Brazil, and coast of Pacific Ocean. They are known from Erycina by not having the pit in the hinge for the ligament. Fig. 109. C. Braziliensis.

CAPULUS. Montf. Fam. Calyptracea, Lam.—Descr. Obliquely conical, posteriorly recurved; apex pointed, sub-spiral; aperture large, rounded, oval; with two muscular impressions, lateral, meeting behind; epidermis horny, rather velvetty. Britain, Mediterranean, West Indies, California, Australia.

CARDIACEA. (Cardiacées, Lam.) A family of the order Conchifera Dimyaria, Lam. Most of the genera of shells contained in this family are included in the very extensive family of Conchacea, in the system of De Blainville. They are described as having irregularly formed cardinal teeth, generally accompanied by one or two elongated lateral teeth. Most of the species are ventricose, and have regular radiating ribs. This family contains the genera Cardium, Cardita, Cypricardia, Hiatella, Isocardia, and others enumerated in the explanation of figures 122 to 130. Their characters may be thus explained.

1. Cardium. Two cardinal and two lateral teeth in each valve, including Hemicardium, Papyridea and Aphrodita, in the last of which the teeth are nearly obsolete. Fig. 122, 123, 123*, 123**.

2. Venericardia. Two oblique cardinal teeth, one elongated; including Cardita, which has the umbones nearly terminal. Pachymya may probably be included, but the hinge is not known. Fig. 121, 124, and 130.

3. Hippopodium. One elongated cardinal tooth. Fig. 129.

4. Megalodon. Hinge broad, septiform, with a large tooth in the centre of one valve. Fig. 127.

5. Isocardia. Teeth laminar; umbones spiral. Fig. 126.

6. Cardilia. The same, with a septiform posterior laminar tooth.

7. Hippagus. Shaped like Isocardia, without teeth. Fig. 128.

CARDILIA. Desh. Fam. Cardiacea, Lam. A genus formed for the reception of Isocardia semi-sulcata, Lam. and a small fossil shell, which Deshayes had formerly named Hemi-cyclonosta Michelini; thus described, (translation) "shell oval, oblong, longitudinal, white, heart-shaped, ventricose, with large prominent umbones; hinge with a small cardinal tooth and a pit at the side; a spoon-shaped projection for the reception of the internal ligament; anterior muscular impression rounded, not deep; the posterior being upon a thin, horizontal lamina, projecting in the anterior." Deshayes further remarks that although the animal is unknown, the relations of the genus may be established by means of the shell alone. Two families contain all the shells which have the internal ligament inserted in a spoon-shaped projection; in the one, that of the Anatinæ, the ligament is supported upon a little bone, which is not soldered to the hinge; in the other, that of the Mactraceæ, this little bone has no existence. In the former, all the shells are inequivalve; in the latter equivalve. And M. Deshayes, considering that the valves are equal, and that there is no separate bone to the hinge, is of opinion that the genus ought to be placed near the Lutrariæ, and not far from the Anatinæ. C. semisulcata, fig. 501, 2.

CARDINAL MARGIN. The edge of a bivalve shell on which the teeth is placed.

CARDINAL TEETH. The teeth upon the hinge directly beneath the umbones of a bivalve shell, as distinguished from the lateral teeth, which are placed at a distance on each side. In Venus, fig. 119, the cardinal teeth, are marked by the letter c.

CARDIOCARDITES. Bl. A genus separated from Cardita, Auct. Thus described (translation) "oval species, with the inferior margin nearly straight, or a very little inflated, crenulated and completely closed. Ex. La C. Ajar, Adans Seneg. pl. 16. fig. 2."

CARDISSA. Sw. A genus composed of those species of Cardium Auct. which are heart-shaped. Ex. C. dionæum, fig. 122. And C. Cardissa.

CARDITA. Brug. Fam. Cardiacea, Lam. Submytilacea, Bl.—Descr. Equivalve, inequilateral, ovate, subquadrate or oblong, marked externally by ribs radiating from the umbones and terminating in a crenulated margin on the inner surface; cardinal teeth in one valve, one long, thick, oblique; another short, more straight; in the other valve one long, oblique, thick. Muscular impressions two in each valve, rather oval; palleal impression not sinuated.—Obs. This description includes Lamarck's genus Venericardia, which, although consisting of the more oblong species, is not considered sufficiently distinct to justify the separation. Cypricardia is distinguished from this genus by a remote lateral tooth. Mediterranean, Africa, East Indies, &c. Cardita calyculata, fig. 124.

CARDIUM. Auct. Fam. Cardiacea, Lam. Conchacea, Bl.—Descr. Equivalve, sub-equilateral, sometimes gaping posteriorly, ornamented on the outside by ribs radiating from the umbones; cardinal teeth, two in each valve, locked into each other crosswise, lateral teeth, two in each valve, remote; muscular impressions, two in each valve; palleal impression entire. Ligament external, inflated.—Obs. Although this genus includes many remarkable forms, the characters are so easily defined that there is no difficulty in distinguishing it from any other genus. C. angulatum, fig. 123. C. Grœnlandicum, fig. 123*. Aphrodita, Lea. C. Hemicardium, fig. 123**. fig. 122. C. Dionæum. It is somewhat surprising that this genus, which contains some of the most beautiful forms of bivalve Testacea, should have been left till quite lately without any attempt to revise the species and settle the synonyms. The author of this Manual has endeavoured to remedy this defect by publishing a catalogue of all the species hitherto known, which amount to 97, including many new species described by him in the "Proceedings of the Zoological Society," in 1840. Parts 46 to 51, 149 and 150, and 177 to 184 of his Conchological Illustrations contain figures of 60 species. Cardia are frequent in all climates.

CARINARIA. Auct. Class, Cephalopoda. Division, Monothalamia, Lam. Fam. Nectopoda, Bl.—Descr. Symmetrical or nearly so, conical, thin, glassy, fragile, patelliform; with a fimbriated dorsal keel; apex convolute, bent forwards; aperture oval, pointed at the dorsal extremity. Hab. Amboyna, Indian Ocean, and Mediterranean Sea.—Obs. A most singular and beautiful shell, remarkable for its transparency, its fragile structure, and the dorsal keel, whence it derives its name. It was once so rare that a single specimen was known to realize one hundred guineas. Fig. 488. C. Mediterranea.

CARINATED. (From Carina, a keel.) Applied to any shell having a raised, thin ledge, passing round a whorl or any other part of a shell, as in Carinaria, fig. 488.

CARINEA. Sw. A genus formed for the reception of Ovulum gibbosum, Auct. and similar species, fig. 443.

CARINELLA. Adanson. Lutraria papyracea, Lam. Ligula, Leach. Fam. Mactracea, Lam. Fig. 77.

CARINIDEA. Sw. A sub-genus of the genus Canthorbis, Sw. (Turbo.) thus described, "Imperforate; spire pyramidal, acute; basal whorl concave beneath, and carinated round its circumference; aperture oval, entire, slightly angulated at the base of the pillar, which turns inwards. C. concavus, Martini, 168, fig. 1620, brevispinosus? Sow. Gen. (Turbo,) fig. 1."

CAROCOLLA. Auct. Fam. Colimacea, Lam.—Descr. Orbicular, depressed, with the outer sides of the whorls angulated or keeled, whorls few; peritreme reflected; columella contiguous to the axis; epidermis thin.—Obs. This genus differing from Helix only in the whorls being angulated, is hardly distinct enough from the latter to justify the separation. In De Ferrusac's system these species constitute the division Helicigona, of the genus Helix. C. Lamarckii, fig. 277. East and West Indies, Philippines, South America and Europe.

CARTILAGE. See Ligament.

CARYCHIUM. Müll. Fam. Auriculacea, Bl. Colimacea, Lam.—Descr. Oblong or cylindrical, with gradually increasing whorls, few in number; aperture straight, short, with a fold on the columella.—Obs. This genus of minute land shells differs from Auricula chiefly in the soft parts. De Furrusac enumerates three species, C. Lineatum, C. Corticaria, (Odostomia, Flem.) and C. Minimum, fig. 301. De Blainville places it in his genus Auricula, as "species with two folds and a posterior tooth on the columella," giving a figure of A. Mysotis as his example, and quoting the name Phitia, Gray. Europe.

CASSIDARIA. Lam. (From Cassis) Fam. Purpurifera, Lam. Entomostomata, Bl.—Descr. Oval, ventricose, spirally grooved and tuberculated, with a short turrited spire and a large aperture, terminating anteriorly in a recurved canal; outer lip thickened, reflected, undulated or denticulated; inner lip expanded over a part of the body whorl and the columella, with part of its lower edge free.—Obs. The recent species of this genus are not numerous; the few fossil species occur in the tertiary strata. C. carinata is found in Calc-grossier and London Clay. In general form this resembles Cassis, but is at once distinguished by the canal, which does not turn abruptly back, but is slightly curved upwards. Oniscia (C. Oniscus, &c. Lam.) is distinguished by the shortness of the canal, and the granulated surface of the inner lip. Fig. 407. C. Echinophora. Mediterranean.

CASSIDEA. Sw. (from Cassis.) A genus composed of those species of the genus Cassis, Auct. which have the "aperture wide; outer lip never broad or flattened, but sometimes slightly inflected; inner lip spreading, but never dilated or detached beyond the base into a prominent rim." East Indies. Ex. C. Glauca, fig. 411.

CASSIDULA. Humph. Pyrula, Auct.

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

CASSIS. (A helmet.) Fam. Purpurifera, Lam. Entomostomata, Bl.—Descr. Oval or triangular, ventricose, thick, generally tuberculated, with a short varicose spire; aperture long, sometimes narrow, with the outer lip thickened and reflected, generally denticulated; the inner lip spread over the surface of the body whorl, indented and incrassated at its inner edge; canal turned suddenly over the back of the shell. Hab. Seas of tropical climates. The fossil species are rare, occurring in the tertiary strata.—Obs. The large, common species of this well known genus are used for shell cameos and as ornaments on chimney pieces, grottos, &c. and are remarkable for the triangular disc, presented by the inner lip, which, in many species, is thickened and spread over the front of the body whorl and the angulated outer lip. The smaller, more rounded species, which have widened apertures, have been separated by Swainson, under the generic name Cassidea. The C. rufa, coarctata, &c. are formed by Mr. Stutchbury into a new genus under the name Cypræcassis, for reasons which will be stated under the word. Cassidaria is distinguished by the gradual curve of the canal. Fig. 410 is Cassis tuberosa, diminished.

CASTALIA. Lam. Fam. Trigonées, Lam.—Descr. Fluviatile, equivalve, inequilateral, trigonal, with corroded umbones; hinge with two laminar, transversely striated teeth, one of which is posterior, remote from the umbones, short, divided, the other anterior, elongated; epidermis thick; internal surface pearly. Lamarck, in describing this shell, states, that he regards it as intermediate between Trigonia and Unio. It should, however, certainly have been placed in the family of "Nayades," and perhaps should form a part of the genus Unio itself. C. ambigua, Lam. fig. 140. South America.

CATILLUS. Brong. (A little dish.) Inoceramus, Sow.

CATOPHRAGMUS. Sow. (From Κατω, beneath; φραγμος a place paled in.) Order, Sessile Cirripedes, Lam.—Descr. Light principal valves, cemented side by side in a circle; eight small pointed valves beneath, covering the joints of the upper circle, and numerous still smaller valves forming the base of the shell; operculum, four valves.—Obs. This is the only genus of Sessile Cirripedes, consisting of eight principal valves, excepting Octomeris, which is destitute of the accessary pieces from which the genus derives its name. Fig. 23. C. imbricatus. South Africa.

CAUDAL CANAL. The elongated hollow process which terminates the aperture anteriorly of some univalve shells. For instance, Murex Haustellum, fig. 396, has an elongated caudal canal.

CELLANTHUS. Montf. Vorticialis, Bl. A genus of microscopic Foraminifera.

CELLULACEA. Bl. The second order of Cephalophora, Bl. consisting of doubtful microscopic bodies, with a number of variously arranged shells, as distinguished from the true Polythalamia, Bl. or chambered shells. See Foraminifera.

CEMORIA. Flemingii. Leach. A small patelliform shell, differing from Fissurella, in having the fissure placed behind the apex, which is produced, pointed and incurved. It is the Patella Fissurella, Müll. Patella Noachina, Chemn. F. Noachina, Sow. Puncturella, Lowe. Fig. 244. Cemoria Flemingii. Scotland and Tierra del Fuego.

CENTRAL. A term used to indicate the position of the muscular impression of a bivalve shell when it is near the centre of the inner surface. It is also applied to the siphon perforating the septum of a chambered shell when it is placed near the centre of the plate. Sub-central is also used as a comparative term, to indicate the position of the siphon, or of the muscular impression, is near the centre. Thus in Placuna (fig. 184), the muscular impression is central: in Exogyra (fig. 183), it is sub-central.

CEPA. Humph. Anomia, Linn.

CEPHALOPHORA. Bl. The first class of Malacozoæ, Bl. Divided into: Order 1. Cryptodibranchiata; 2. Cellulacea; 3. Polythalamacea. The first consisting of Cuttle-fish, &c. which are destitute of shells; the second composed of those microscopic cellular bodies, which are regarded as shells by some authors; and the third containing the true chambered shells.

CEPHALOPODA. Lam. (Cephalopodes.) (Κεφαλη, kephale, head; πους, ποδος, podos, foot.) The fourth order of the class Mollusca, Lam. containing molluscs, which are characterized by having a series of arms surrounding the head, which is placed above a sack-shaped body. This order is divided into Polythalamia, or many-chambered shells; Monothalamia, or single-chambered cephalopods; and Sepiaria, or cuttle-fish. Fig. 463 to 488.

CEPOLIS. Montf. Belonging to the genus Helix, Auct.

CERATODES. Guild. (Κερατωδης, like a horn.) A genus composed of the flat, orbicular species of Ampullaria, Auct. which present so near a resemblance to the Planorbes, as to have been considered as belonging to them. Planorbis has, however, a horny texture, and no operculum, and it is always reversed, which may be observed by placing the spire upwards. Fig. 320, represents Ampullaria (Ceratodes) Cornu-arietis.

CERIPHASIA. Sw. A sub-genus of Melanianæ, thus described, "Cerithiform; outer lip thin, dilated at the base; aperture small, slightly emarginate, without any internal groove; inner lip thin. C. sulcata, Sw. fig. 38. p. 204." (Sw. Lard. Cyclop. Malac. p. 342.)

CERITHIUM. Brug. Fam. Canalifera, Lam. Entomostomata, Bl.—Desc. Elongated, ribbed, tuberculated, or rarely smooth, with a lengthened, turrited, pointed, pyramidal spire, consisting of numerous whorls; aperture sub-quadrate, terminated anteriorly by a tortuous canal; outer lip thickened, sometimes reflected, expanded; inner lip thickened posteriorly; operculum horny, spiral, with numerous whorls.—Obs. The fresh-water shells described as Cerithia by Lamarck, are separated under the name Potamis, and may be known by the thick, horny epidermis. Triphora, Desh. has the canal closed, except at the extremities. Cerithium Telescopium, does not appear to present the same characters as the other Cerithia, and has been separated by some writers under the generic name Telescopium. Cerithium Aluco, fig. 372. Mediterranean, East and West Indies, Coasts of the Pacific, Gallapagos, Australia, &c. Some small species are British. Fossils are numerous in the tertiary beds.

CERVICOBRANCHIATA. Bl. The second order of Paracephalophora Hermaphrodita, Bl. containing symmetrical patelliform shells, divided into the families Retifera and Branchifera.

CETOCIS. Montf. Fam. Orthocerata, Lam. and Bl. Placed by De Blainville in his section of Belemnites, characterized as having small folds at the apex. Ex. B. Penicillatus.

CETOPIRUS. Ranz. Coronula Balænaris, Auct. fig. 16.

CHAMA. Auct. Fam. Chamacea, Lam. and Bl.—Descr. Inequivalve, irregular, thick, foliaceous, attached by the umbo of the lower and larger valve. External ligament placed in a groove, following the curve of the umbones. Umbones spiral, coiled round on the back of the valves; hinge with a thick, crenated, lengthened tooth, in one valve, entering a corresponding cavity in the hinge margin of the other; muscular impressions, two in each valve, distinct, lateral.—Obs. The Linnæan genus Chama, included the beautiful shells now called Tridacna. These are exceedingly different from the true Chama, being regular and unattached. The Chama (Tridacna) gigas, when at its full age and development, is the largest shell known. Specimens have occurred weighing upwards of 500 lbs., and measuring two feet across. Diceras may be known from Chama by the spiral horns into which the umbones are produced; Isocardia, by the regularity of the shells, and it is hardly necessary to mention Spondylus, which may be known by the triangular disc between the umbones; Cleidothærus, Stutch. which resembles Chama in general form, has a separate bony appendage attached to the hinge, and may, moreover, be distinguished by its elongated muscular impression. Fig. 153, C. Lazarus. E. and W. Indies.

CHAMACEA. Bl. The seventh family of the order Lamellibranchiata, Bl. containing the genera Chama, Diceras, Etheria, Tridacna, Isocardia and Trigonia.

CHAMACEA. Lam. A family belonging to the order Conchifera Dimyaria, Lam. described as inequivalve, attached, irregular; with or without a single rough tooth on the hinge; with two lateral muscular impressions in each valve. This family contains the genera—

1. Chama. Leafy; umbones spiral. Fig. 153.

2. Etheria. Very irregular, pearly, without teeth. Fig. 155.

3. Diceras. Like Chama, but the umbones free, produced. Fig. 154.

CHAMBERED. When the cavity of a shell is not continuous, but is divided by shelly diaphragms or septa, it is said to be chambered. This is the case with the shells of the Polythalamous Cephalopoda, as in the Nautilus (see Introduction). The character is not confined to these, as it occurs in some species of Spondyli, and in several turrited univalves.

CHAMOSTRÆA. De Roissy. Cleidothærus. Stutch.

CHARYBS. Montf. A genus of microscopic Foraminifera.

CHELIBS. Montf. A genus of microscopic Foraminifera.

CHELINOTUS. Sw. A genus of "Haliotidæ," Sw. including Velutina, Lam. a species of Sigaretus from Tonga, and Coriocella, Bl. Thus described, "Animal cheloniform, broad; depressed; the mantle larger than the shell, lobed in front; tentacula two, short, obtuse; eyes basal; mouth circular; shell ear-shaped, thin, fragile, imperforate; pillar none."

CHELONOBIA. Leach. Coronula Testudinaria, Auct. Fig. 15.

CHERSINA. Humph. Achatina, Lam.

CHICOREUS. Montf. A generic division of the genus Murex, consisting of such species as have three ramified varices. Ex. M. inflatus, fig. 395.

CHILINA. Gray. Fam. Auriculacea, Bl. Colimacea, Lam.—Descr. Oval, thin, covered with an olive green epidermis; spire rather short, consisting of few whorls; aperture large, oval, rounded anteriorly; outer lip thin, joining the inner lip without a sinus; inner lip spread over part of the body whorl, terminating in a thick columella with one or two folds.—Obs. These shells differ from the true Auriculæ in the thinness of the outer lip. C. Dombeyana (Auricula Dombeyana, Auct.) Fig. 300. The illustrated catalogue published by the author (Sow. Conch. illustr. parts 135, 136) contains 13 species. Rivers of South America.

CHILOTREMA. Leach. A sub-genus of Helix, containing Helix lapicida, Auct. Gray, Turton, p. 140.

CHIMOTREMA. ——? Belongs to Helix.

CHIONE. Megerle. Cytheræa maculosa, (fig. 117, c.) sulcata, circinata, &c. Auct. and other similar species.

CHIRONA. Gray. A genus of Balanidæ, the shells consisting of six parietal valves and two opercular valves; the upper edges of the parietal valves are sloped and the structure is not tubular.

CHISMOBRANCHIATA. Bl. The second order of the first section of Paracephalophora Monoica, Bl. Those Mollusca belonging to this order which have shells, have them either internal or external, but always scutiform, with depressed spires and wide, haliotoid, oblique apertures, without a columellar lip properly so called. This order partly answers to the family Macrostomata, in the system of Lamarck. It contains the genera Coriocella, Sigaretus, Cryptostoma, Oxinoe, Stomatella and Velutina.

CHITON. Auct. (χιτον, an integument.) Fam. Phyllidiana, Lam. Class, Polyplaniphora, Bl.—Descr. Oval, consisting of eight arched valves arranged in a series across the body of the animal and fixed in the skin which forms a rim around them, sometimes scaly, spinose, or rugose, sometimes smooth.—Obs. The genus Chiton, commonly called "Coat of Mail," from its resemblance to jointed armour, remains to the present day in exactly the same state with regard to its boundaries as that in which Linnæus found it, and in which he left it. That illustrious Naturalist placed it among the multivalves in his purely Conchological system, although the animal is totally different from the Cirripedes. The shells are prettily marked, and are found attached to the rocks in all seas of Tropical and Southern climates, but fossil species are almost unknown. Fig. 227, C. Spinosus. The genus is divided by Guilding into Chiton, Canthopleura, Phakellopleura, Chitonellus and Cryptoconchus. Zool. Journ. XVII. p. 27. The author of this manual has lately attempted a revision of this interesting but neglected genus, and has given a catalogue of all the species hitherto known, as far as they could be identified among the confused mass of synonyms and descriptions to be found in the works of various Conchological writers. This catalogue is to be found in his Conchological Illustrations, and refers to figures of 102 species, 92 of which are contained in parts 38 to 45, and 159 to 176.

CHITONELLUS. Lam. (From Chiton) Separated by Lamarck from Chiton, on account of the valves being placed at a greater distance from each other, the soft integument of the animal intervening. Fig. 228, C. striatus. Philippines.

CHLOROSTOMA. Sw. A sub-genus of "Trochinæ." Sw. (Trochus) of which C. argyrostoma is given as an example. Sw. Lard. Cyclop. p. 350.

CHONDRUS. Hartmann. Abida, Leach. A genus formed for the reception of Pupa secale, Drap. Pupa Juniperi, Montague, which have plaits in the aperture.

CHRYSOAR. Montf. Probably a species of Orthoceras.

CHRYSODOMUS. Swains. "Distinguished from Fusus, by the comparative shortness of the basal channel, and the ventricose or enlarged shape of the body whorl. The beautiful orange-mouthed Whelk of England is a typical example; and the few others now known are all of a very large size, and chiefly found in Northern Seas, where they represent the more elegant Fusi of tropical latitudes; the outer lip is always thin and smooth." Sw. page 90, paragraph 78, described at page 308.

CHRYSOLUS. Montf. Polystomella, Bl. A genus of microscopic Foraminifera.

CHRYSOSTOMA. Sw. A genus of the family "Rotellinæ," Sw. Thus described "Shell turbinate; the whorls few and convex; aperture effuse, round; inner lip thickened just over, and almost concealing the umbilicus. Nicobaricus, Martini, 182 fig. 1822-5." Sw. Lard. Cyclop. Malac. p. 327.

CHTHALAMUS. Ranz. Fam. Balanidea, Bl. Order, Sessile Cirripedes, Lam.—Descr. "Shell much depressed, valves thick, thickened at the base, with prominent areas; operculum nearly horizontal, composed of four valves."—Obs. This description would apply generically to the shell called Platylepas in the British Museum, only nothing is said about the prominent plates jutting from the internal surface of the valves. The difference between this genus and Balanus consists principally in the horizontal position of the operculum, and general flatness of the shell. C. stellatus, fig. 18.

CIBICIDES. Montf. A genus of microscopic Foraminifera.

CIDARIS. Swains. A genus composed of Turbo Smaragdus, petholatus, and other similar species. The word Cidaris is, however, already in use for a genus of Echinæ.

CIDAROLLUS. Montf. A genus of microscopic Foraminifera.

CILIATED. (ciliæ, hairs.) Having minute hairs as in Orbicula, Lingula, &c. and the jointed feelers of the Cirripedes.

CIMBER. Montf. Navicella, Auct.

CINERAS. Leach. (Cinereus, ash-coloured.) Order, Pedunculated Cirripedes, Lam.—Descr. Animal with a quadrilateral body, supported on a fleshy peduncle, with an opening in front of the upper part for the passage of a bunch of ciliated tentacula. Immediately above this aperture is a pair of small elongated valves, placed in a nearly horizontal position; at the lower part is another tripartite pair placed perpendicularly, one on each side, and a narrow, angulated, keel-shaped piece placed at the back.—Obs. The nearest approach to this genus is Otion. (C. Vittatus, fig. 42.) Found upon substances floating in the sea.

CINEREOUS. (Cinereus) Ash-coloured.

CINGULA. Fleming. Rissoa, Leach.

CIONELLA. Jeffreys. Fam. Colimacea, Lam.—Descr. Oblong or elongated; last whorl large; apex rather acute; columella, sub-interrupted; aperture canaliculated, sub-effuse at the base; margins very unequal; no umbilicus. Bulinus octonus, lubricus, acicula, &c. Auct. C. lubrica, fig. 285.

CIRCE. Schum. Venus castrensis, fig. 117 d. V. sulcatina, arabica, pectinata, Auct. and other similar species.

CIRRIPEDES. Lam. The tenth class of invertebrated animals, so named from the curled and ciliated branchia which protrude from the oval aperture of the shells. The class Cirripedes of Lamarck constitutes the entire genus Lepas of Linnæus. They are divided into two sections; first, Sessile Cirr. attached by the basal portion of the shell; second, Pedunculated Cirr. supported upon a Peduncle. Figs. 14 to 45.

CIRROBRANCHIATA. Bl. The first order of Paracephalophora Hermaphrodita, Bl. This order has been formed for the purpose of giving a place in the system to the genus Dentalium. The animal of which has lungs, consisting of numerous filaments, having their basal origin in two radical lobes under the neck.

CIRRUS. J. Sowerby (cirrus, a tendril.) Fam. Turbinacea, Bl. and Lam.—Descr. Spiral, conical, with a hollow axis; whorls contiguous, numerous, rounded, or slightly angulated.—Obs. This fossil genus resembles Trochus, from which it is known by the deep funnel-shaped umbilicus. Fig. 349, C. nodosus.

CISTULA. Humph. Cyclostoma, Lam.

CLANCULUS. Montf. Trochus Pharaonis, Lam.—Obs. This, with several other species, belong more properly to Monodonta, Lam. Odontis, Sow. Fig. 361.

CLATHODON. Conrad. Gnathodon, Gray.

CLAUSILIA. Drap. (Clausium, a valve or folding door.) Fam. Colimacea, Lam. Limacinea, Bl.—Descr. Spire elongated, consisting of many volutions; aperture small, sub quadrate, having several tooth-shaped folds on the columella. A small, elastic, shelly plate, attached to the columella within, called the Clausium, its office being to enclose the aperture when the animal has retired within the shell.—Obs. This last character distinguishes it from the Pupæ, to some of which it bears a very near resemblance. Hab. Land, in the central and southern parts of Europe, several British species. Fig. 295, C. Macascarensis.

CLAUSIUM. A name applied to the beautiful contrivance whence the genus Clausilia derives its name, consisting of a little bony tortuous plate, placed in a groove on the columella. Here it serves the purpose of a door, which, when not prevented by counteracting pressure, springs forward on its elastic ligament, and encloses the animal in his retirement. The aperture is opened by pushing back the clausium into the groove.

CLAUSULUS. Montf. Conch. Syst. 1, 179. A genus of microscopic Foraminifera.

CLAVA. Humph. Cerithium, Lam.

CLAVAGELLA. Lam. (Clava, a club.) Fam. Tubicolæ, Lam. Pyloridea, Bl.—Descr. Two irregular flattish valves, one fixed or soldered, so as to form part of the side of an irregular shelly tube; the other free within the tube near the base.—Obs. The shells composing this genus are found in stones, madrepores, &c. and appear to form the connecting link between Aspergillum, which has both valves cemented into the tube; and Fistulana, in which both are free. Fig. 45, a fossil Clavagella. Found recent on the Coast of Malta and New South Wales.

CLAVALITHES. Sw. A genus composed of some fossil shells, separated from the genus Fusus, which, having the general form of Turbinella Rapa, &c. are considered by Swainson, as holding an intermediate station between Fusus and the Turbinellidæ.—Descr. "Unequally sub-fusiform; the body whorl, and spire, being conic; and the canal suddenly contracted and attenuated; terminal whorls papillary; inner lip thick; pillar smooth, C. longævus, clavellatus, Noæ, ponderosus, Sw."—Obs. The papillary spire may form a sufficient reason for separating this genus from Fusus, while the absence of plates on the columella places them at a still greater distance from Turbinella.

CLAVATE. When one extremity of the shell is attenuated, and the other becomes suddenly ventricose or globular, it is said to be Clavate. Ex. Murex Haustellum, fig. 396.

CLAVATULA. Lam. The generic name by which Lamarck originally distinguished those species of Pleurotoma which were remarkable for the shortness of their canals. In his system, however, they are re-united to Pleurotoma. Fig. 381, P. Strombiformis.

CLAVICANTHA. Sw. A genus separated from Pleurotoma, Lam. consisting of species, which are described as "thick, sub-fusiform; the surface rugose, and the whorls sub-coronated; channel short; slit assuming the form of a short, broad sinus. C. imperialis, E. M. 440, spirata, E. M. 440, fig. 5, conica, E. M. 439, fig. 9, echinata, E. M. 439, fig. 8, Auriculifera, E. M. 439, fig. 10."

CLAVICLE. (clavis, a key.) A little key. This term is applied to the bony appendage in the hinge of some species of Anatina, (those included in the generic term Lyonsia) Cleidothærus, Myochama, &c.

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

CLAVUS. Montf. A genus of microscopic Foraminifera.

CLEIDOTHÆRUS. Hutch. (Θαιρος, hinge, Κλεις, clavicle.) Fam. Chamaceæ or Myariæ, Lam.—Descr. Inequivalve, irregular, solid, attached; with one cardinal, conical tooth in the free valve, entering a corresponding indenture in the other; and an oblong shelly appendage, fixed by an internal cartilage in a groove under the umbones; muscular impressions, two in each valve, one elongated, the other uniform.—Obs. This shell is like Chama in general form, but is distinguished by the clavicle or shelly appendage from which its name is derived. Fig. 75. New South Wales.