A Conchological Manual, George Brettingham Sowerby [little readers .TXT] 📗

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.

 

ORBICULA. Umbones central; byssus passing through a hole in the

       flat valve. Fig. 201.

 

ATRYPA. Without foramen or space between the valves. Fig. 203.

 

PRODUCTA. The same, valves produced, overwrapping; including

       Leptæna. Fig. 206, 206*.

 

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.

 

SPIRIFER. The same, with deep triangular area; spiral folds in

       the interior; including _Trigonotreta_ and _Cyrtia_. Fig. 204, 214,

       215.

 

THECIDIUM. Large valve attached; curved ridges in the inner

       surface; two jutting points or teeth on the hinge. Fig. 216.

 

CRANIA. Attached by the surface of the valve; muscular

       impressions four, forming a face. Fig. 197, _a_, b.

 

PYCNODONTA. Irregular; hinge with raised pointed teeth. Fig.

       217, 218.

 

PENTAMERUS. Valves divided by septa; including _Gypidia_. Fig.

       210 to 213.

 

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