Part 24

TEREBELLUM. Lam. (_Terebra_, an augur?) _Fam._ Convolutæ, Lam. Angyostomata, Bl.--_Descr._ Smooth, slender, oblong, sub-cylindrical; spire obtuse, short, sometimes hidden; (Seraphs, Montf.) aperture long, narrow posteriorly, wider anteriorly; outer lip slightly thickened, truncated, unconnected at the base with the columella; inner lip thin, smooth, nearly straight, spread over a portion of the body-whorl, continued in a ridge above the sutures of the spire.--_Obs._ Montfort has separated the fossil species with hidden spires, under the name Seraphs. (T. convolutum, Lam.) Only one recent species is known, of which there are several varieties, one spotted, one marked in sub-spiral lines, another in patches. It is brought from the East Indies. Fig. 451, T. convolutum; 452, T. subulatum.

TEREBRA. (_An augur, a piercer._) _Fam._ Purpurifera, Lam. Entomostomata, Bl.--_Descr._ Subulate, elongated, pointed, turrited; spire long, consisting of numerous whorls; aperture small terminating in a short, reflected canal; outer lip thin; columella tortuous; operculum horny. The recent species are mostly tropical.--_Obs._ Nearly all the species enumerated by Lamarck and other authors are included by De Blainville in his genus Subula; those few species which that conchologist left in the present genus, being shorter and more ventricose than the others, approximate in shape to some of the Buccina, and are distinguished by Mr. Gray under the generic name Bullia. It seems strange, that De Blainville, being convinced of the necessity of separating the two groups, and consequently applying a new generic term to one of them, should have given that term to the larger number and the more typical species of the Lamarckian genus. Fig. 427, Bullia vittata. (Terebra.) Fig. 428, Terebra maculata. (Subula.)

TEREBRALIA. Sw. A genus of "Cerithinæ," Sw. thus described: "Outer lip much dilated, generally uniting at its base to the inner lip; leaving a round perforation at the base of the pillar; channel truncate; operculum round: palustre. Mart. f. 1472." Sw. p. 315.

TEREBRATING SHELLS. (_Terebro_, to pierce.) Shells which reside in holes pierced in rocks, wood, &c. by means of some corrosive secretion of the animal. _Ex._ Pholas, Teredo, &c.

TEREBRATULA. Brug. (_Terebrans_, bored.) _Fam._ Brachiopoda, Lam.--_Order._ Palliobranchiata, Bl.--_Descr._ Inequivalve, equilateral, oval or sub-trigonal, ventricose or compressed, attached by a tendon passing through an opening in the dorsal, or upper and larger valve, the umbo of which advances beyond that of the other valve; hinge destitute of a ligament, with two teeth in the dorsal valve, locked into corresponding cavities in the ventral, or lower valve, and with two curious processes originating at the umbo of the lower valve, presenting, in some species, the appearance of fine winding tape, advancing towards the front of the valve, and again receding to the centre, where the ends unite; muscular impressions two, placed near the centre of each valve.--_Obs._ The Terebratulæ are included in the genus Anomia in the system of Linnæus. The recent species are not very numerous--they are found in all climates. The fossil species are more numerous than the recent ones, occurring in the secondary and tertiary formations. T. Psittacea, fig. 202.

TEREDINA. (From Teredo.) _Fam._ Tubicolæ, Lam. Adesmacea, Bl.--_Descr._ Valves equal, inequilateral, with prominent umbones, as it were soldered to the outside of the rounded end of a shelly tube, of which they form a part; aperture of the tube partly divided; a flat accessary valve placed on the umbones.--_Obs._ This genus, which is only known in a fossil state, is distinguished from Teredo, by the valves being fixed on the tube, and the tube being closed at one extremity. Fig. 46, 47, T. personata.

TEREDO. Auct. (_A piercer._) _Fam._ Tubicolæ, Lam. Adesmacea, Bl.--_Descr._ Valves equal, inequilateral; presenting when closed, an orbicular figure, with a large angular opening in front, and a rounded opening at the back; placed at the anterior extremity 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:

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

2. 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.

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 and Ranellæ there are still to be traced in the shells of each of those genera, several constant and well marked distinctions, by which they maybe at once recognized. In the Ranellæ, the varices run in two rows along the spire; in the Murices, they form three or more rows; but in the Tritons, they do not follow each other, _i.e._ they do not occur in the same part of each volution. The large species of Triton, are sometimes used as trumpets. The Tritons are brought from the Mediterranean, Ceylon, the East and West Indies, and South Seas. Fig. 398 to 401.

TRITONIDEA. Sw. A genus of "Buccininæ," Sw. thus described: "Shell bucciniform, but the basal half is narrowed, and the middle more or less ventricose; spire and aperture equal. Pillar at the base with two or three obtuse and very transverse plaits, not well defined; outer lip internally crenated and with a superior siphon; inner lip wanting, or rudimentary." This genus is the same as the one first distinguished by Mr. Gray under the name of Pollia. We do not regret the discovery made by Mr. Swainson of that name being previously occupied for a genus of Lepidopterous Insects. Fig. 415, represents Tritonidea articularis. (Pollia, Gray.)

TRIVIA. Gray. A genus composed of those small species of CYPRÆA, Auct. which are characterized by small ridges on the dorsal surface, and have the anterior of the columella internally concave and ribbed. C. Pediculus. Auct. fig. 449, 450.

TROCHATELLA. Sw. A sub-genus of Helicinæ, consisting of those species which are acute and trochiform.

TROCHIA. Sw. A genus of the family Buccininæ, thus described: "shape intermediate between Purpura and Buccinum; whorls separated by a deep groove; inner lip when young, depressed, when adult, thickened, convex and striated; basal canal very small. T. sulcatus. E. M. 422. f. 4." Sw. Malac. p. 300.

TROCHIDON. Sw. A sub-genus of "Trochinæ," Sw. Lardn. Cyclop. Malac. p. 351.

TROCHILÆA. Sw.? PILEOLUS, Auct.

TROCHURUS. Humph. MONODONTA. Lam.

TROCHUS. Auct. (_A top._) _Fam._ Turbinacea, Lam. Goniostomata, Bl.--_Descr._ Turbinated, thick, striated, tuberculated or smooth; spire elevated, conical, consisting of numerous whorls; under surface discoid; aperture more or less depressed in an oblique direction, generally angular; columella arcuated, more or less prominent at its union with the outer lip, contiguous to the axis of the shell; operculum horny, orbicular, with numerous whorls.--_Obs._ Lamarck distinguished this genus from Turbo by the general form, which is more conical, and the aperture, which is angulated, while that of Turbo is rounded. Monodonta or Odontis is only separated on account of the notch at the termination of the columella. But these characters glide so imperceptibly from one genus to the other, that there is no line of demarcation to be found but in the operculum. Accordingly, Sowerby (in Gen. of Sh. 37.) has stated his reasons for considering as Trochi, all the species which have horny opercula; and as Turbines, all those which have testaceous opercula. Fig. 358 to 360. The Trochi are found in all climates.

TROPÆUM. Sow. CRIOCERATITES.

TROPHON. Montf. MUREX Magellanicus, Auct. and several other species which belong more properly to Fusus than to Murex.

TRUMPET SHELL. A large species of Triton (variegatus), used by natives of South Sea Islands as a trumpet, to call warriors and herds of cattle together. It answers the purpose tolerably well, producing a very sonorous blast.

TRUNCATED. (_truncus_, cut short.) Terminating abruptly, as it were cut short. _Ex._ Solenensis, fig. 60.

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

TRUNCATELLA. Risso. A genus composed of several species of land shells which have been confounded by some authors with Cyclostoma. The genus is thus described: "Shell turriculated, cylindrical, decollated or truncated at the apex, no epidermis; aperture oval, short, with lips continuous, simple." _Ex._ Truncatella truncatulina, Lowe, Zool. Journ. t. 5. p. 80. Our plates, fig. 520, 521. It is found on the shores of Britain, the Mediterranean, and West Indies.

TUBA. Lea. A genus of small fossil shells, described as resembling Turbo, but with the aperture more like that of Melania. Lea. Contrib. Geol.

TUBERCLE. (_tuberculus._) A small swelling excrescence, or knob.

TUBERCULATED. Having a number of small lumps or pimples, as Turrilites, fig. 483.

TUBICINELLA. Lam. (_Tubicen_, a trumpeter.) _Order_, Sessile Cirripedes, Lam.--_Descr._ A cylindrical tube, composed of six elongated valves jointed together side by side, striated longitudinally, surrounded by concentric rings; aperture circular, enclosed by an operculum of four valves, placed perpendicularly in an epiphragm.--_Obs._ The Tubicinellæ are found with nearly the whole shell buried in the thick skin of the whale. T. Balænarum.

TUBICOLARIA. Lam. (_Tuba_, a tube; _cola_, an inhabitant.) A family of the order Conchifera Dimyaria, Lam. consisting of bivalves soldered as it were within, or connected with, a testaceous tube. The genera contained in this family may be thus distinguished.

1. ASPERGILLUM. Valves fixed, tube perforated and fringed. Fig. 44.

2. TEREDINA. Valves fixed, prominent, tube closed at one end. Fossil. Fig. 46, 47.

3. CLAVAGELLA. One valve fixed, the other free. Fig. 45.

4. TEREDO. Both valves free, tube open at both ends. Fig. 48, 49.

5. FISTULANA. Valves free, tube closed at one end, straight, long. Fig. 53, 54.

6. GASTROCHÆNA. Valves free, tube closed at one end, short, bulbous. Fig. 52.

TUBIVALVES. Bl. Shells composed of two valves connected in a tube, corresponding with the family Tubicolæ of Lamarck.

TULIPARIA. Sw. A sub-genus of "Coronaxis," Sw. Lardn. Cyclop. Malac. p. 311.

TURBINACEA. Bl. The sixth family of Polythalamacea, Bl. containing the genera Cibicides and Rosallites, microscopic Foraminifera.

TURBINACEA. Lam. A family of the first section of the order Trachelipoda, Lam. containing the following genera.

1. SOLARIUM. With umbilicus reaching to the apex; including _Bifrontia_ and _Orbis_. Fig. 353 to 356.

2. ROTELLA. A callosity on the under side. Fig. 357.

3. PHASIANELLA. Oval; operculum shelly. Fig. 367.

4. PLANAXIS. Columellar lip flat; aperture notched. Fig. 365.

5. TURBO. Top-shaped; mouth generally round; operculum shelly. Fig. 368.