280 TUB1CINELLA. 



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 ter- 

 mination of the columella. But these characters glide so imper- 

 ceptibly from one genus to the other, that there is no line of de- 

 marcation 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. 



TROP^UM. 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. SO. Our plates, 

 fig. 520, 521 . It is found on the shores of Britain, the Mediter- 

 ranean, and West Indies. 



TUBA. Lea. A genus of small fossil shells, described as resem- 

 bling 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 



