Part 7

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. ([Greek: Belemnon], _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. ([Greek: Bussos], _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.