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

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.

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.

 

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

 

TEREDINA. Valves fixed, prominent, tube closed at one end.

       Fossil. Fig. 46, 47.

 

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

 

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

 

FISTULANA. Valves free, tube closed at one end, straight, long.

       Fig. 53, 54.

 

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.

 

SOLARIUM. With umbilicus reaching to the apex; including

       _Bifrontia_ and _Orbis_. Fig. 353 to 356.

 

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

 

PHASIANELLA. Oval; operculum shelly. Fig. 367.

 

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

 

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

       368.

 

TROCHUS. Top-shaped; mouth generally angulated; operculum horny,

       consisting of many whorls; including _Elenchus_. Fig. 358, 359,

       361.

 

MARGARITA. Operculum horny, consisting of few whorls; pearly.

       Fig. 362.

 

LITTORINA. Similar, not pearly; including _Assiminnea_. Fig.

       363, 363*.

 

PHORUS. Attaching dead shells, stones, &c. Fig. 360.

 

MONODONTA or ODONTIS. A notch and prominent point at the lower

       part of the aperture. Fig. 366.

 

LACUNA. With an umbilicus. Fig. 364.

 

TURRITELLA. Elongated, screw-shaped. Fig. 369 to 371.

 

   TURBINATED. (_Turbo_, a top,) Top-shaped. The term is applied generally

   to those shells which are large at one extremity, and narrow to a point

   at the other. _Ex._ Trochus, fig. 358; Turbinellus, fig. 382.

 

   TURBINELLUS. Auct. (_A little top._) _Fam._ Canalifera, Lam.

   Siphonostomata, Bl.--_Descr._ Turbinated, thick, wide near the apex,

   generally tuberculated; spire short, depressed, mammillated; aperture

   rather narrow, terminating anteriorly in an open canal; outer lip

   thickened within; columella having from three to five prominent,

   compressed, transverse folds. The species of this genus are mostly

   tropical.--_Obs._ The Turbinelli are a well marked genus of marine

   shells, the species of which are numerous. No fossil species are known.

   The genus Cancellaria makes the nearest approach to Turbinellus in some

   characters, but may be distinguished by the roundness of its form, the

   raised lines inside the outer lip, and the obliquity of the folds on

   the columella. Fig. 382 to 384.

 

   TURBO. Auct. (_A top._) _Fam._ Cricostomata, Bl. Turbinacea,

   Lam.--_Descr._ Turbinated, solid, ventricose, generally grooved or

   tuberculated; spire short, pointed; aperture generally rounded,

   sub-effuse anteriorly, entire; operculum shelly, solid, incrassated on

   the outer side, horny and sub-spiral on the inner side. The Turbines

   are mostly tropical.--_Obs._ The only certain means of distinguishing

   this extensive genus of marine shells from Trochus, is the operculum,

   which in the latter genus is horny, spiral, and composed of a great

   number of whorls. The Trochi, however, are in general more conical, and

   flatter at the under side of the whorls, and this constitutes Lamarck's

   distinction between the genera. T. setosus, fig. 368.

 

   TURGID. (_Turgidus._) Puffed up, swollen, inflated. This term is

   applied synonymously with Ventricose.

 

   TURRICULA. Humph. MELANIA, Auct.

 

   TURRICULACEA. Bl. The seventh family of the Order Polythalamacea, Bl.

   containing the genus Turrilites, fig. 483.

 

   TURRILITES. Lam. (_Turris_, a tower; [Greek: lithos], a stone.) _Fam._

   Turriculacea, Lam. Ammonacea, Bl.--_Descr._ Chambered, turrited,

   spiral; septa sinuous and lobate, perforated by a siphon; aperture

   rounded, with the outer lip expanded. This genus, which is

   distinguished from the other Ammonacea by having the spire produced,

   _i. e._ not being convolute, consists of several species, occurring

   only in chalk-marl. Fig. 483.

 

   TURRIS. Montf. A genus composed of those species of MITRA, Auct. which

   have the whorls angulated, with the aperture lengthened and undulated.

 

   TURRITED. The spire of an univalve shell is said to be _turrited_ when

   the whorls of which it is composed are regulated so as to have the

   appearance of little turrets rising above each other, as in Mitra, fig.

   431.

 

   TURRITELLA. Lam. (_A little tower._) _Fam._ Turbinacea, Lam.

   Cricostomata, Bl.--_Descr._ Turrited, elongated, generally grooved

   spirally; spire pointed, consisting of numerous whorls; aperture

   rounded or angulated; inner and outer lips thin, confluent anteriorly;

   operculum horny.--_Obs._ The shells composing this well defined genus,

   are commonly called screws, a name to which the spiral grooves of most

   of the species seems to entitle them. Fig. 370, T. imbricata.

 

   TYMPANOSTOMA. Schum. (_Timbrel mouth._) POTAMIS, Brongn.

 

   TYPHIS. Montf. A genus composed of MUREX tubifer, Auct. and other

   similar species, which have the canal closed and a perforated tube

   between each varix on the angulated part of the whorls. Besides the

   fossil species originally described, there are now five species known,

   which are figured in part 200, of the Conchological Illustrations by

   the Author. Typhis tubifer, fig. 397.

 

   ULTIMUS. Montf. (_The last._) A genus composed of OVULUM gibbosum,

   Auct. fig. 443, and other species in which the canals are not

   distinctly defined, nor elongated. This fanciful name is given to the

   genus on account of its being described in the last page of the book.

 

   UMBILICATED. (_Umbilicatus._) Having an umbilicus, as Nautilus

   umbilicatus.

 

   UMBILICUS. (_A navel._) The hollow formed in spiral shells when the

   inner side of the volutions do not join each other, so that the axis is

   hollow. The umbilicus is marked with the letter u in Helix algira, fig.

The term is also used to express any small, neat, rounded hollow.

 

   UMBO. (_The boss of a buckler or shield._) The point of a bivalve shell

   above the hinge, which constitutes the apex or nucleus of each valve,

   from which the longitudinal rays diverge, and the lines of growth,

   commencing at the minutest circle, descend in gradually enlarging

   concentric layers to the outer margin. The umbones will be marked with

   the letter _u_, in Cytherea, fig. 117.

 

   UMBRELLA. (_A little shade._) _Fam._ Semiphyllidiana, Lam. Patelloidea,

   Bl.--_Descr._ Patelliform, sub-orbicular, compressed, rather irregular;

   apex slightly raised, placed near the centre; margin acute; internal

   surface with a central, callous, coloured disc, surrounded by a

   continuous, irregular muscular impression.--_Obs._ This genus is known

   from Patella, by its continuous muscular impression. It is commonly

   called the Chinese Umbrella shell. There are but two species at present

   known; the U. Mediterranea, and the U. Indica, fig. 233.

 

   UNDATED. (_Unda_, a wave.) Waved.

 

   UNDULATED. (_Undulatus._) Minutely waved.

 

   UNGUICULATED. (_Unguis_, a nail or hoof.) An unguiculated operculum is

   one in which the layers are disposed laterally, and the nucleus

   constitutes part of the outer edge.

 

   UNGULINA. Daud. (_Ungula_, a nail or claw.) _Fam._ Mactracea, Lam.

   Conchacea, Bl.--_Descr._ Equivalve, sub-orbicular, sub-equilateral,

   with margins entire, simple, closed all round; hinge with one short,

   sub-divided cardinal tooth in each valve, and a very minute additional

   tooth in one valve, an oblong ligamentary pit divided into two

   portions, one of which receives the cartilage, the external ligament is

   immediately below the umbones; muscular impressions, two in each valve,

   oblong; impression of the mantle entire. U. transversa, fig. 88. Coast

   of Africa.

 

   UNI-AURICULATED. Having one AURICLE. See AURICULATED.

 

   UNICORNUS. Montf. MONOCEROS, Auct.

 

   UNIO. (_A pearl._) _Fam._ Nayades, Lam. Submytilacea, Bl.--_Descr._

   Inequilateral, equivalve, regular, free, pearly within, covered by a

   smooth epidermis without; umbones prominent, generally corroded;

   muscular impressions two in each valve, lateral, distant; the anterior

   composed of several small divisions; hinge varying in age, species, and

   individuals.--_Obs._ The above description is framed so