291 MOLLUSCA. BRANCHIFERA. Bulla. 



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

 tudinally ; entirely white ; crown umbilicate ; at each extremity 

 three transverse punctured stria?. 1 '' 



Dr Turton, Zool. Journ. No. vii. 3G4. t. xiii. f. 6 — British Channel. 



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

 reference is evidently here intended for the B. stria/a of Lamarck, not to the 

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

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

 strife 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. 



Linn. Syst. i. 1183, Pult. Dorset. 40. Don. Brit. Shells, t. cexx. Mont- 

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



Length 1 inch, breadth f ths, 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 suborbicular, patulous, moniliform- 

 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 ; bre.adth 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 cateme, 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. emarginata. — Shell gibbous ; aperture emarginate ; 

 pellucid, smooth ; lip subarcuated. 



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.Jlexilis. — Shell pellucid, horn-coloured ; apex white, 



opake, with a single volution. 



Laskey, Mont. Test. Brit. Supp. 1C8. Wern. Mem. i. 396. t. 8. f. 6 



Dunbar, rare. 



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

 dry. — This shell probably belongs to the genus Sigaritus. 



