CONOVULUS. 191 



upon the columella, and sometimes in the throat ; its 

 peristome more or less thickened. Septa of the spire even- 

 tually obliterated. No operculum. 



Animal with two subtriangular tentacula, and two sessile 

 eyes placed at their inner bases. Foot rounded at both 

 extremities, and often sulcated transversely in the centre, 

 so as to divide it into two disks. 



Some very interesting observations on the animals of 

 the British species of this genus, by Mr. W. Clark, are 

 contained in the Annals of Natural History, for December, 

 1850, and July, 1851. 



C. bidentatus, Montagu. 



White ; outer lip simple, throat smooth ; pillar with two folds. 



Plate CXXV. fig. 1, 2. 



Voluta bidentata, Mont. Test. Brit. Suppl. p. 100, pi. 30, f. 2. — Turt. Conch. 



Diction, p. 253. — Dillwyn, Recent Shells, vol. ii. p. 507. 



— Wood, Index Testae, pi. 19, f. 21 (magnified). 



„ alba, (scarcely of Mont. Test. Brit. p. 235, not Suppl. p. 101, or of 



Maton and Rack. Trans. Linn. Soc. vol. viii. p. 130), Turt. 



Conch. Diction, p. 250. 



Auricula bidentata (not Gould), Ferus. Tabl. Syst. Moll. p. 103. — Jeffreys, 



Trans. Linn. Soc. vol. xvi. p. 368. — Brit. 

 Marine Conch, p. 144. 

 „ alba, Ferus. Tableau System. Moll, (no desc). — Jeffreys, Trans. 

 Linn. Soc. vol. xvi. p. 368. — Forbes, Malacol. Monens. p. 12. 

 — Brit. Marine Conch, p. 145. 

 Volvaria „ Fleming, Brit. Animals, p. 333. 

 Acteon bidentatus, Fleming, Brit. Animals, p. 337. 

 Auricula erosa, Jeffreys, Trans. Linn. Soc. vol. xvi. p. 369. 

 Conoculus bidentatus, Gray, Manual L. and F. W. Shells, p. 227, pi. 12, f. 145. 

 — Brit. Marine Conch, p. xxxiii. — Clark, Ann. Nat. 

 Hist, new scr. vol. vi. p. 445. 

 „ albus, Gray, Manual L.and F. W. Shells, p. 227, pi. 12, f. 146.— 

 Brit. Marine Conch, p. xxxiii. f. 25. 

 Auricula Micheli, Mittre, Revue Zoo], Soc. Cuvier. 1841, p. 66 ? 

 Jaminia bidentata, Brown, Illust. Conch. G. B. p. 22, pi. 8, f. 7. 

 Auricula dubia, Cantraine, Bull. Acad. Sc. Brux. vol. ii. p. 383.; Mem. Acad. 

 Sc. Brux. vol. xiii. p. 172 ? 



