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

four former belonging to that class

   of microscopic fossils, now termed Foraminifera; the genus Nummulites,

   although large, may probably belong to the same class, and perhaps it

   would have been better to have included the remaining genus, Nautilus,

   in the next family, from which it differs in having the septa which

   divides the chambers simple at their edges.

 

_Ammonacea_ (plates, fig. 477 to 484). The edges of the septa of

   these are all more or less sinuous and complicated. This family

   contains the following genera, Ammonites, Ammonoceras, Baculites, and

   Turrilites, the latter of which presents a singular anomaly in having

   an oblique spire, like that of the order Trachelipoda, while it is

   divided into chambers by sinuous septa.

 

Order _Monothalamous Cephalopoda_.

 

The only shells included in this order belong to the genera Argonauta

(plates, fig. 485), placed here by Lamarck, and Bellerophon (plates, fig.

486 and 487), a fossil genus subsequently added.

 

Order _Heteropoda_.

 

The singular and beautiful transparent shell contained in this order, under

the generic name Carinaria, forms a covering to a small portion of an

animal, equally remarkable and equally distinct from those of all other

orders.

 

 

 

The above arrangement, although far from perfect, and requiring numerous

modifications, is perhaps liable to as few objections as any other yet

proposed, and will certainly be more easily understood by those who have

not the opportunity of studying the soft parts of the animal.

 

       *       *       *       *       *

 

CONCHOLOGICAL MANUAL.

 

   ABIDA. Leach. A genus founded on a species of PUPA, which has the

   peristome slightly reflected, and numerous plaits in the aperture. Pupa

   Juniperi, Pupa secale, Draparnaud. Great Britain; also Central and

   Southern Europe.

 

   ABRA. Leach. A genus composed of AMPHIDESMA tenue, prismaticum, and

   other small thin species. British Channel and Mediterranean. _Fam._

   Mactracea.

 

   ABSIA. Leach. LITHOTRYA, Sowerby. _Fam._ Pedunculated Cirripedes.

 

   ACAMAS. Montfort. BELEMNITES multiforatus, Blainville. A species

   described as being perforated at the apex, by a stellated perforation.

   No species of Belemnite at present known agreeing with the description;

   it is supposed to have been taken from a broken specimen.

 

   ACANTHOCHETES. A name given to a species of Chiton having bunches of

   bristles at the sides of the valves.

 

   ACARDO. Commerçon. Described from a pair of bony plates, taken from the

   vertebræ of the Whale, and mistaken for a bivalve shell, destitute of a

   hinge.

 

   ACARDO. Swainson. A generic term applied by Swainson to the nearly

   toothless species of Cardium, named C. edentulum by some authors; C.

   Greenlandicum by others: fig. 123*.

 

   ACASTA. Leach. _Order_, Sessile Cirripedes, _Lamarck_. BALANUS

   _Montagui_, Sowerby. A small genus separated from Balanus, on account

   of the cup-shaped base, but re-united by Sowerby, who shews, in his

   Genera of Shells, that this is a merely accidental circumstance,

   resulting from the situations in which the shells acquire their growth.

   If, for instance, the Balanus be attached to a flat surface, in an open

   situation, the base will be short and flat; if it be placed in a hollow

   among other growing substances, it will be lengthened out in order that

   the aperture of the shell may be even with the outer surface of the

   surrounding mass; and if, as in the Acastæ, it be imbedded in a soft

   and loose substance, the base, being left to itself, will take a

   regular form. The Acastæ are found imbedded in sponges. _Ex._ Balanus

   Montagui, of Great Britain, fig. 26. Also found in the Pacific ocean

   and Philippines.

 

   ACAVUS. Montfort. _Fam._ Limacinea, Blainville; Colimacea, Lamarck. A

   division of the genus Helix, which may be considered synonymous with De

   Ferrusac's sub-genus Helicogena. De Montfort has given H. Hæmastoma, as

   an example. Fig. 267.

 

   ACCESSARY VALVES, are the smaller or less important testaceous plates,

   found on the hinge or dorsal margins of the true valves of some shells.

   Example, the small plates on the hinge of Pholas, fig. 55, a. The

   Pholades were placed by Linnæus and Bruguière among multivalve shells.

 

   ACEPHALOPHORA. Blainville. (_a_, without; [Greek: kephale], head.) The

   third class of the type Malacozoaria, Bl. including all bivalve shells,

   the animals of which have no distinct head. This class corresponds with

   the Conchifera of Lamarck, and is divided into the orders

   Palliobranchiata, Rudistes, Lamellibranchiata, and Heterobranchiata,

   the last of which contains no genera of testaceous Mollusca.

 

   ACHATINA, Auctorum. _Fam._ Colimacea, Lam. (from Achates, an agate.)

   _Fam._ Limacineæ, Bl. _Gen._ POLYPHEMUS, Montf.--_Descr._ Shell oval or

   oblong, sub-turrited, light, thin; aperture oval, or pyriform; outer

   lip sharp; columella smooth, tortuous, truncated, so as to form a notch

   at its union with the outer lip.--_Obs._ It is from this notch that we

   are enabled to distinguish Achatinæ from Bulini, which, moreover,

   generally have a reflected outer lip. The Polyphemi of Montfort have an

   undulation in the centre of the outer lip. Achatina Virginea, fig. 286.

   Polyphemus Glans, fig. 288. These land shells are found in various

   parts of the globe, but attain the greatest size and richness of

   colouring in tropical climates; particularly in the West India Islands.

 

   ACHATINELLA. SOW. A small group of shells, differing from Achatina in

   having the inner edge of the outer lip thickened, and a slight groove

   near the suture of the spire. Fig. 287. Sandwich Islands.

 

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

 

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

 

   ACIONA. Leach. A genus described by De Blainville as consisting of

   those species of Scalaria, the whorls of which do not touch each other.

   If this account be correct, the genus proposed by Leach will include

   the typical species of Scalaria, such as S. pretiosa.

 

   ACME. Hartmann. A genus formed of TURBO fuscus, Walker. AURICULA

   lineata, Drap. thus described--"Shell sub-cylindrical, with a blunt

   tip; mouth ovate, simple, thin, slightly reflected over the pillar,

   forming a slight perforation." The animal is said to resemble a

   Cyclostoma, but has no operculum. Auricula lineata, Drap. Hist. 57, t.

   3, fig. 20, 21. Southern Europe.

 

   ACTEON. Montf. TORNATELLA, Lam.

 

   ACTINOCAMAX. Stokes. A genus of Belemnitiform Fossils.

 

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

   fig. 227.

 

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

   fig. 313.

 

   ACUS. Humphrey. TEREBRA of Lamarck.

 

   ACUTE. Sharp, pointed, or sharp-edged.

 

   ADDUCTOR MUSCLE. That which draws the two valves of a shell together,

   and leaves a mark on the inner surface of each, called the MUSCULAR

   IMPRESSION.

 

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

 

   ADESMACEA. Bl. (_a_, without; [Greek: Desma], _desma_, ligament.) The

   10th family of the order _Lamellibranchiata_, Bl. composed of Mollusca

   which either bore tubular dwellings in rocks, wood, &c. or live in

   testaceous tubes, their shells being consequently destitute of the

   hinge ligament. The action of opening and shutting the valves being

   limited to the narrow space to which they are confined, or else the

   valves themselves being soldered into the tube, renders it unnecessary

   for them to have a ligament to keep them in their places. The genera

   Pholas, Teredina, Fistulana, and Septaria, belong to this family, which

   corresponds in part with the families Tubicolaria and Pholadaria, of

   Lamarck.

 

   ADNA. Leach. One of the genera separated by Leach from _Pyrgoma_, and

   characterized as consisting of an upper valve, supported on a

   funnel-shaped base, which is not buried in the coral to which it is

   attached, like Pyrgoma, but is seen externally. The operculum consists

   of four valves. Adna, fig. 32. British Channel and Mediterranean.

 

   ADNATE. A term applied by some authors to those shells belonging to the

   family of Unionidæ, which have the valves joined together at the dorsal

   margin, not like other bivalves, by a distinct ligament, but by the

   substance of the shell itself, the valves appearing to grow together in

   such a manner that they cannot be separated without one of them being

   broken as will be seen in our figure of Dipsas plicatus, fig. 142. This

   circumstance has been made the foundation of specific and even generic

   distinctions, for which however it is insufficient, because many

   species which when young are "_adnate_," when fully grown have their

   valves joined together only by a ligament.

 

   ÆGLIA. Say. A division of "Unionidæ," described as having the "shell

   cuneate; bosses prominent; cardinal teeth much compressed, placed on

   one side of the bosses. Æglia ovata, _Say_. Occidens _Lea_. Am. Tr.

   iii. pl. 10." Lardner's Encyclopedia of Malacology.

 

   AGANIDES. Montf. ORBULITES, Lam.

 

   AGATHIRSES. Montf. SILIQUARIA, Auct.

 

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

 

   AKERA. Bl. The fourth family of the order Monopleurobranchiata, Bl.

   containing the genera Bulla, Bullæa and Bellerophon, which, excepting

   the last, constitutes the family Bullæana, Lam.

 

   AKERA. A genus of extremely light, horny shells, resembling BULLA, from

   which it differs, in the outer lip being separated from the body whorl,

   which is elastic. _Ex._ Bulla fragilis, fig. 247.

 

   ALÆA. Jeffrey's. A genus of minute land shells, resembling _Vertigo_,

   but separated because they are dextral, while Vertigo is sinistral.

   _Ex._ fig. 292. A. marginata, Pupa marginata, Drap. found in marshy

   ground, roots of trees, moss, &c. Britain and Southern and Central

   Europe.

 

   ALASMODON. Say. A division of the genus UNIO, Auct. consisting of those

   species which have cardinal, but no lateral teeth. _Ex._ A.

   complanatus, fig. 141. North America and Europe.

 

   ALATÆ. Lam. A family of the order Trachelipoda, Lam. containing the

   following genera which may be thus distinguished.

 

ROSTELLARIA. Sinus close to the canal; including _Hippochrenes_,

       and _Aporrhais_, Fig. 402 to 404.

 

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

 

PTEROCERAS. Same, digitated. Fig. 405.

 

   ALATED. (From Ala, a wing.) Winged, a term applied to shells, when any

   portion of them is spread out in any direction, as in fig. 403.

   Hippochrenes, Montf. and fig. 147, Unio Alatus.

 

   ALCADIA. Gray? (B. M. Syn. p. 134) Helicinæ which have a notch in the

   aperture. A distinction which it is impossible to maintain. See

   HELICINA.

 

   ALATUS. Humphrey. STROMBUS, Auct.

 

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

 

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

 

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

 

   AMALTHUS. Montf. A. margaritaceus, Montf. is a species of AMMONITES

   described as very flat, keeled, with an angular aperture. It belongs to

   the family Ammonacea, Lam.

 

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

   species.

 

   AMBIGUÆ. Lam. The fourth section of the order Conchifera Dimyaria,

   containing the family Chamacea, fig. 153 to 155.

 

   AMICULA. A genus formed for the reception of CHITON amiculatus, Auct.

   the valves of which are covered by an integument; so as to be

   completely hidden externally.

 

   AMIMONUS. Montf. CONILITES ungulatus, Knorr. A species distinguished

   only by being slightly curved; _Fam._ Orthocerata, Lam.

 

   AMMONACEA. Bl. The fourth family of the order Polythalamia, Bl. or

   chambered shells, described as thin, chambered, discoidal, convolute,

   symmetrical, generally compressed, with visible whorls. This last

   character is used in De Blainville's System to distinguish the

   Ammonacea from the Nautilacea. This family contains the genera

   Discorbites, Scaphites, Ammonites, and Simplegas.

 

   AMMONACEA. Lam. The seventh family of Polythalamous Cephalopoda, Lam.

   containing the genera Ammonites, Orbulites, Ammonoceras, Turrilites and

   Baculites, to which may be added Amalthus, Simplegas, Ellipsolites,

   Nautellipsites, Hamites, Icthyosarcolites, and other genera mentioned

   in the list of figures 477 to 484.

 

   AMMONITES. Auct. (from Jupiter Ammon.) _Fam._ Ammonacea, Lam. and

   Bl.--_Descr._ Symmetrical, convolute, discoidal, orbicular; chambers

   numerous, divided by lobated, branched or sinuous septa, perforated by

   a Siphon; aperture generally more or less modified by the last whorl.

   The fossils of the secondary strata which compose this genus are

   numerous and well known; they are vulgarly termed "snake-stones," and

   some of them are extremely beautiful, particularly when the internal

   structure is exhibited by a section. There is some difficulty in

   distinguishing them from the Fossil Nautili, for although the whorls,

   being visible and the Septa _sinuous_, may be taken as the

   characteristics of the Ammonites, yet there are several species which

   partake the characters of both. The Orbulites of Lamarck (fig. 479) for

   instance, have sinuous septa like Ammonites, but the last whorl covers

   those which precede it as in Nautilus. Simplegas Montf. and Bl. (fig.

   475) has the whorls visible externally and the septa simple. Ammonites

   is figured in the plates (478).

 

   AMMONOCERAS, or AMMONOCERATITES. Lam. (from _Ammon_ & [Greek: Keras],

   ceras, horn.) The shells