294 MOLLUSCA. BRANCHIFERA. Bulla. 



179. B. alba. — " Shell oval, oblong ; slightly striated longi- 

 tudinally ; entirely white ; crown umbilicate ; at each extremity 

 three transverse punctured striae." 



Dr Turton, Zool. Journ. No. vii. 364. t. xiii. f. 6 — British Channel. 

 Dr Turton adds, " They are more elongated than the BuUa ampulla (the 

 reference is evidently here intended for the B. striata of Lamarck, not to the 

 true Ampulla), and essentially differ in having only three rather remote trans- 

 verse striae at each end, whereas on the latter shell there are seven or eight 

 striae on the lower extremity, and none on the upper." 



** Shells probably concealed, destitute of' a cuticle, and under 

 the integuments. 



180. B. aperta. — Shell smooth, with indistinct lines of growth ; 

 suborbicular, depressed ; aperture expanded ; pillar short 



jLinn. Syst. i. 1183, Pi^?/. Dorset. 40. Dow. Brit. Shells, t. ccxx. Mont- 

 Test. Brit. 208. vig. ii. f. 1, 3 — Not common. 

 Length 1 inch, breadth aths, thin, pellucid, white ; apex simple ; body 

 slightly involuted. Animal pellucid, white, with minute opake specks ; sto- 

 mach of three testaceous plates. 



181. B. punctata. — Shell suborbiculai', patulous^ monihform- 

 ly striated longitudinally. 



Adams, Linn. Trans, v. 2. t. i. f. 6, 8 — B. catena, Mont. Test. Brit. 



215. t. 7. f. vii On the English coast, not common. 



Length about |th of an inch ; breadth rather less ; apex rounded, with a 

 cavity exposing a volution. Montagu mentions " a variety with a more 

 transparent zone, taking in eight or ten of the catenae, which are more strong- 

 ly defined; the rest of the shell appears as it were frosted, and not so glossy, 

 possessing a subumbilicus ; and the outer margin of the aperture, close to the 

 body, is winged, or reflected a little, forming a depression or sulcus on that 

 part." 



182. B. emarglnata. — Shell gibbous ; aperture emarginate ; 

 pellucid, smooth ; lip subai'cuated. 



Adams, Linn. Trans, v. 2. t. i. f. 9, 11.— On the English coast, rare. 



183. B. denticidata. — Shell white, pellucid, oblong, nearly 

 equal, obtuse, smooth ; outer lip ending in a tooth retrally. — 

 Perhaps only the young of B. aperta. 



Adams, Linn. Trans, v. 1. t. i. f. 3, 6 — Coast of Pembroke. 



184<. B. flexilis. — Shell pellucid, horn-coloured ; apex white, 

 opake, with a single volution. 



Laskey, Mont. Test. Brit. Supp. 168. Wern. Mem. i, 396. t. 8. f. 6 — 

 Dimbar, rare. 

 Length half an inch, wrinkled; flexible in a moistened state; brittle when 

 dry This shell probably belongs to the genus Sigaritus. 



