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

of an irregular,

   flexuous, elongated tube, open at both ends; the anterior termination

   divided in a double aperture opened and closed at the will of the

   animal by two opercula.--_Obs._ This genus of Molluscous Animals, is

   remarkable for boring holes in wood, which are filled by their

   elongated tubes, and give it a honey-comb appearance. Fig. 48. T.

   Navalis. Fig. 49, a piece of bored wood.

 

   TERMINAL. When the umbones of a bivalve shell are placed at or near the

   extremity, as in Mytilus, fig. 158, Pinna, fig. 162, they are said to

   be _terminal_. The same term is also applied to the nucleus of an

   operculum, when it forms an extreme point, or is close to one of the

   edges.

 

   TESSELLATED. (Wrought in chequer-work). A term applied to the colouring

   of shells, when arranged in regular defined patches like a tessellated

   pavement.

 

   TESTACELLA. (_Testa_, a shell.) _Fam._ Limacinea, Lam. and

   Bl.--_Descr._ Haliotoid, compressed; aperture wide, oblique; columella

   flat, oblique; spire short, flat, consisting of less than two

   whorls.--_Obs._ This shell which is extremely small compared with the

   animal, is placed upon its back, near the posterior extremity. The

   animal is found in some of our gardens, and very much resembles the

   common garden slug. Fig. 261, T. Haliotoidea.

 

   TESTACEOUS. (_Testa_, a shell.) Shelly. Testaceous Mollusca, are soft

   animals having shells. A testaceous operculum is one composed of shelly

   matter.

 

   TETRACERA. Bl. The first family of the order Polybranchiata, Bl.

   containing no genera of testaceous mollusca.

 

   TEXTILIA. Sw. A sub-genus of Conus, consisting of Conus bullatus, &c.

   Sw. Malac. p. 312.

 

   TEXTULARIA. Defr. A genus of microscopic Foraminifera.

 

   THALAMUS. Montf. A genus described as resembling Conilites, but curved

   and granulated.

 

 THALLEPUS. Sw. A genus of "Aplysianiæ," Sw. thus described: "Body more

   slender and fusiform;" (than Aplysia,) "the lobes of the mantle short,

   and incapable of being used for swimming; tentacula two, large, ear

   shaped; eyes not visible. T. ornatus, _Sw._ Sp. Nov." Sw. p. 359.

 

   THALLICERA. Sw. A generic name under which Swainson distinguishes

   AMPULLARIA Avellana, Auct.

 

   THECIDIUM. (_Thecas_, a box.) _Fam._ Brachiopoda, Lam. _Order_,

   Palliobranchiata, Bl.--_Descr._ Lower valve concave, sub-trigonal, with

   the umbo produced into a triangular, slightly incurved beak, and with

   two short, pointed processes advancing from beneath the umbones; upper

   valve flat, rounded square, with a short, blunt appendage, formed to

   fit between the tooth-like process of the other valve; its inner

   surface ornamented with symmetrically curved ridges.

 

   THECOSOMATA. Bl. The first family of the order Aporobranchiata, Bl.

   containing the genera Hyalæa, Cleodora, Cymbulia, Pyrgo.

 

   THELICONUS. Sw. A sub-genus of Conus. Lardn. Cyclop. Malac. p. 312.

 

   THELIDOMUS. Sw. A generic name under which Swainson has described a

   division of the genus Helix, and which he has also used to designate a

   genus in the family of "Rotellinæ," founded upon an aggregate of loose

   particles collected and agglutinated in a spiral form by the larva of

   an insect. Sw. Malac. p. 330 and 353.

 

   THEMEON. Montf. A genus of microscopic Foraminifera.

 

   THEODOXUS. Montf. A division of the genus Nerita. Fig. 324, N.

   virginea.

 

   THETIS. Sow. (_A sea nymph._) A genus of fossil shells, described as

   resembling Mactra, but not having the internal ligament, and having

   several small, acuminated, cardinal teeth, but no lateral teeth. It

   resembles Tellina in some degree, but has not the posterior fold.

 

   THIARELLA. Sw. A sub-genus of Mitra, Lardn. Cyclop. Malac. p. 319.

 

   THRACIA. Leach. _Fam._ Lithophagidæ, Lam. Pyloridea, Bl. A genus

   described as intermediate between Anatina, and Mya, and in some degree

   resembling Corbula. T. corbuloides, fig. 93.

 

   THUNDER-STONES. One of the vulgar appellations which have been applied

   to shells of the genus Belemnites.

 

   THIATYRA. Leach. A genus composed of AMPHIDESMA _flexuosa_, Lam. and

   similar species, belonging more properly to the genus LUCINA.

 

   TIARA. Sw. A genus of "Mitranæ," Sw. thus described: "Aperture narrow,

   linear, or of equal breadth throughout; outer lip and base of the body

   whorl contracted, the former generally striated; an internal canal at

   the upper part of the aperture; shell (typically) turrited, and equally

   fusiform; representing the _Muricidæ_ and Cymbiola." Sw. Malac. p. 319.

   The principal difference between Tiara and Mitra appears to be that in

   the latter, the aperture is more linear and contracted in the centre.

   Mitra Episcopalis is an example.

 

   TINOPORUS. Montf. A genus of microscopic Foraminifera.

 

   TIRANITES. Montf. A division of the genus Baculites.

 

   TOMELLA. Sw. A genus of "Pleurotominæ," Sw. thus described: "Fusiform,

   smooth; the spire of very few whorls, and not longer than the channel;

   inner lip with a thick callosity at the top; the slit short and wide;

   lineata, En. Méth. 440, f. 2, clavicularis, Ib. f. 4. filosa. En. Méth.

   440, f. 6. lineolata. Ib. f. 11." Sw. p. 314.

 

   TOMOGERUS. Montf. ANASTOMA, Auct. Fig. 471.

 

   TONICHIA. Gray. Syn. B. M. p. 126. A genus composed of those species of

   Chiton which have the margin smooth.

 

   TORNATELLA. Auct. _Fam._ Plicacea, Lam.--_Descr._ Oval, spirally

   grooved; spire short, rather obtuse, consisting of few whorls; aperture

   long, narrow, rounded anteriorly; outer lip simple; inner lip thin,

   slightly spread, columella spiral, incrassated, confluent with the

   outer lip. The recent species are few. Several fossil species occur in

   London Clay, Inferior Oolite and Calcaire-grossièr. Monoptygma, Lea,

   resembles this genus, but has a fold on the inner lip. Fig. 343, T.

   solidula.

 

   TORTUOUS. (_Tortuosus_) Twisted. This adjective is sometimes applied as

   a specific name; as Arca tortuosa.

 

   TRACHELIPODA. Lam. ([Greek: trachêlos], _trachelos_, a neck; [Greek:

   poda], _poda_, foot.) The third order of the class Mollusca, in the

   system of Lamarck. The trachelipodous mollusca are described as having

   the posterior part of the body spirally twisted and separated from the

   foot; always enveloped in a shell. The foot is free, flat, attached to

   the base of the neck. Shell spiral, and enclosing the animal when at

   rest. This order contains the families, Colimacea, Lymnacea, Melaniana,

   Peristomiana, Neritacea, Janthinea, Macrostomata, Scalariana, Plicacea,

   Canalifera, Alata, Purpurifera, Columellaria, Convolutæ. The genera

   belonging to these families, are represented in the plates, fig. 264,

   to 462.

 

   TRANSVERSE. (Crosswise.) A shell is said to be transverse, when its

   width is greater than its length, that is, when it is longer from one

   side to the other than from the umbones to the ventral margins. The

   term is applied by some authors to express the direction of the lines

   of growth in bivalve shells, and the spiral lines in spiral shells. See

   CONCENTRIC.

 

   TRAPEZIUM. Meg. CYPRICARDIA, Lam.

 

   TRAPEZIFORM, or

 

   TRAPEZOID. ([Greek: trapezion], _trapezion_, _trapezium_; [Greek:

   eidos], _eidos_, form.) Having four unequal and unparallel sides. _Ex._

   Cucullæa, fig. 133.

 

   TRIBULUS. Klein. RICINULA, Lam.

 

   TRICHOTROPIS. Brod. and Sow. ([Greek: Trichos], _trichos_, hair;

   [Greek: tropis] _tropis_, keel.) _Fam._ Purpurifera, Lam.--_Descr._

   Turbinated, keeled, thin, umbilicated; aperture longer than the spire,

   entire; columella obliquely truncated; outer lip thin, sharp; epidermis

   horny, produced into long hairs at the angles of the shell; operculum

   horny, with the nucleus lateral.--_Obs._ Although the shells of this

   genus have something of the shape of Turbo, they are distinguished from

   that genus at once by the thinness of the shell. They are also known

   from Buccinum, by the absence of a canal. Only two or three species are

   known, which belong to the Northern and Arctic Oceans. T. bicarinata,

   fig. 429.

 

   TRIDACNA. Auct. _Fam._ Tridacnacea, Lam. Chamacea, Bl.--_Descr._

   Equivalve, regular, inequilateral, radiately ribbed, adorned on the

   ribs with vaulted foliations, waved at the margins, with a large,

   anterior hiatus close to the umbones, for the passage of a large

   byssus, by which the animal fixes itself to marine substances; hinge

   with a partly external ligament; two laminar teeth in one valve, one in

   the other.--_Obs._ The beautiful shells composing this genus are of a

   delicate white colour, tinged with buff. One species, the T. gigas,

   attains a remarkable size, measuring from two to three feet across, and

   weighing five hundred pounds. Tridacna is distinguished from Hippopus

   by the large opening in the hinge. T. elongata, fig. 157.

 

   TRIDACNACEA. Lam. A family belonging to the first section of the order

   Conchifera Dimyaria, Lam. described as regular, equivalve, solid, and

   which are remarkable for the deeply sinuated or undulated ventral

   margin. This family contains the genera:

 

HIPPOPUS. Valves closed at or near the hinge. Fig. 156.

 

TRIDACNA. An hiatus near the hinge. Fig. 157.

 

   TRIDENTATE. (_Tridentatus_.) Having three teeth, or salient points.

   _Ex._ Hyalæa tridentata, fig. 226.

 

   TRIGONA. Schum.? Triangular species of CYTHEREA, such as C. lævigata,

   Triplas corbicula, ventricosa, bicolor, &c. Fig. 117 _b._

 

   TRIGONACEA. Lam. A family belonging to the order Conchifera Dimyaria,

   containing the genera Trigonia and Castalia, the latter of which ought

   to be removed to the Nayades. Fig. 139, 140.

 

   TRIGONAL. Triangular, having three sides.

 

   TRIGONELLA. Humph. MACTRA, Auct.

 

   TRIGONIA. Brug. ([Greek: trigônon], _trigonon_, triangular.) _Fam._

   Trigonata, Lam. Camacea, Bl.--_Descr._ Equivalve, inequilateral,

   transverse, sub-trigonal, costated and granulated without, pearly and

   iridescent within, denticulated on the inner margin, rounded

   anteriorly, truncated posteriorly; hinge with four oblong, compressed,

   diverging teeth in one valve, receiving between their grooved sides,

   two similar teeth in the other; ligament external, thick; muscular

   impressions two in each valve.--_Obs._ Only one recent species of this

   marine genus is known, the T. pectinata, which comes from New Holland;

   and was formerly so rare, that a much worn odd valve has been sold for

   a considerable sum. It is of a brilliant pearly texture within, tinged

   with purple or golden brown. Fossil species occur in Lias, upper and

   lower Oolite, and Green-sand. T. Pectinata, fig. 139.

 

   TRIGONOSEMUS. König. A genus composed of species of TEREBRATULA, Auct.

   which have one valve produced into a beak, perforated, or as it were

   truncated at the apex. T. lyra, fig. 208, differing from Terebratula

   lyra, Lam.

 

   TRIGONOSTOMA. A sub-genus of Helix, with a trigonal aperture. Gray's

   Turton, p. 139.

 

   TRIGONOTRETA. König. A genus composed of species of Terebratula, Auct.

   which have the hinge of the larger valve produced into a triangular

   disc, divided by a triangular foramen in the centre. Spirifer, Sowerby,

   belongs to this genus. Fig. 214, 215.

 

   TRILOBATE. ([Greek: Treis] three; [Greek: lobos], division, lobe.)

   Divided into three lobes or principal parts. Ex. Malleus, Fig. 165.

 

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

 

 

Class CIRRIPEDES.pg. 4

 

   TRIPARTITE. (_Tripartitus_) composed of or divided into three separate

   parts.

 

   TRIPHORA, or TRISTOMA. Deshayes. A genus composed of small reversed

   species of CERITHIUM, Auct. which have the anterior canal closed at the

   anterior of the aperture, but opened at the extremity, and a small

   tubular opening on the upper part of the whorls, making three openings

   on the body whorl. This genus stands in the same relation to Cerithium

   as the Typhis to Murex. Fig. 375 in the old plates, and fig. in the new

   plates.

 

   TRIPLEX. Humph. MUREX, Linn.

 

   TRIPLODON. Spix. HYRIA, Auct.

 

   TRIPTERA. Quoy et Gaimard, CUVIERA, Fer. Described in the Voyage de la

   Coquille, and represented as a molluscous animal destitute of a shell.

 

   TRIQUETRA. Bl. Triangular species of VENUS Auct.

 

   TRISIS. Oken. ARCA tortuosa, Auct.

 

   TRISTOMA. Described as TRIPHORA.

 

   TRITON. Auct. _Fam._ Siphonostomata, Bl. Canalifera, Lam.--_Descr._

   Oblong or oval, thick, ribbed or tuberculated, with discontinuous

   varices placed at irregular distances; spire prominent, mammillated;

   aperture round or oval, terminating anteriorly in a generally long,

   slightly raised canal; columellar lip granulated or denticulated; outer

   lip thickened, reflected, generally denticulated within; epidermis

   rough; operculum horny.--_Obs._ However nearly allied the Tritons may

   appear to be to the Murices