CYLICHNA. 519 



0. UMBILICATA, MoiltagU. 



Miuuto, oblong-subcylindraceous, spirally strlulate ; crown 

 not attenuated, strongly umbilicated, volutions not visible ex- 

 ternally. 



Plate CXIV. c. fig. 9. 



Bulla umhilicata, MoNT. Test. Brit. vol. i. p. 222 (not figure).— Maton and 

 Rack. Trans. Linn. Sec vol. viii. p. 129. — Turt. Conch. 

 Diction, p. 22 (size ?). — Fleming, Brit. Animals, p. 293. — 

 Brit. Marine Conch, p. 141. — Dillw. Recent Shells, vol. i. 

 p. 497. — Gratel. Sur les Bull, (and in Bull. Bordeaux), 

 p. 23. 



BulliTia „ Macgilliv. Moll. Aberd. p. 190, probably. 



Volvaria „ Brown, Illust. Conch. G. B. p. 3, not figure. 



„ suhcylindrka. Brown, Illust. Conch. G. B. p. 3, pi. 19, f. 19, 20.— 

 Thompson, Ann. Nat. Hist. vol. xv. p. 315. 



The strong apical perforation, the broader and less pro- 

 duced shape, the absence of all posterior attenuation, or 

 anterior tumidity, seem the combined characters by which 

 the present form may be distinguished from the three pre- 

 ceding ones. Instead of being planulate or retuse in the 

 middle it is more or less ventricose ; hence the outer lip is 

 more equably curved, neither being perceptibly contracted 

 in the middle, nor swollen below. When perfectly fresh, 

 more or less distinct, though at times interrupted, spiral 

 striulse are rendered visible by a powerful lens, but not 

 being deeply graven are easily worn away, so that the 

 majority of specimens appear smooth. The aperture 

 scarcely bends over the crown so much as in nitidula, nor 

 does it project above so much as in conulus. Occasionally 

 there is a slight chink behind the pillar lip, which in the 

 more characteristic specimens is subpliciform and arches a 

 little to the right at its anterior extremity, so as to render 

 the base of the aperture more truly rounded (not merely 



