216 bullidj:. 



Diaphana hiemalis. 



Fig. 100. 



Shell minute, globular, very thin, dusky, no spire perceptible, with a small 

 umbilicus. 



Bulla hiemalis, CouTHOUT, Bost. Jonrn. Nat. Hist. ii. 180, pi. 4, fig. 5 (1839). — De Kat, 



N. Y. Moll. 18, pi. 35, tig. 335. — Gould, Inv. 163, tig. 100. 

 Diaphana hiemalis, Stijipson, Check Lists, 4 (1860). 



Shell globular, very thin and brittle, transparent, of a brownish 

 tinge, except near the tip, where it is whitish ; body whorl envelop- 

 ing all the rest, so as to leave no perceptible spire, and 

 Fig. 506. j^^f^i'ijeti -with the lines of growth ; the aperture is narrow be- 

 XJ hind, but greatly enlarged forwards ; the outer lip revolves, 

 ^naUs' fro^^^ i^s junction behind, nearly a third of a revolution be- 

 fore it turns forwards ; a thin ])late of callus is spread over 

 the inner margin, and rises so as to form a small but distinct um- 

 bilicus. Length and breadth, about one tenth of an inch. 



Procured from codfish taken off Provincetown, in about thirty 

 fathoms water ; Grand Manan (^Stimpson) ; Bristol, Maine. 



It is a remarkable shell, sufficiently distinguished by its globular 

 form and its peculiar lip. 



Diaphana debilis. 



Fig. 95. 



Shell obliquely ovate, small, transparent, inflated, smooth, partially umbihcated; 

 whorls four, terminating on a level; pillar lip terminating abruptly in front. 



Bulla debilis, Gould, Silliman's Journ. Old Series, xxxviii. 196 (1840) ; Inv. 164, fig. 



95. —De Kay, N. Y. Moll. 17, pi. 35, fig. 329. 

 Diaphana debilis, Stimpson, Check Lists, 4 (1860), 



Shell small, obliquely ovate, tumid, thin and brittle, greenish- 

 white ; whorls four, all rising to about the same height, division 

 distinct, each very convexly rounded ; last whorl the whole 



rig. 507. 7 J J •> 



length of the shell, including all the others, and partially 

 detached from them above ; surface without apparent marks ; 

 aperture as long as the shell, widening from behind for- 

 D. debdis. .^^.j^j^^g . outer lip attached behind, a little before the summit 

 of the shell it rises to a level with the spire, and then descends in 

 a regular though slightly waved curve to the front of the pillar, 

 where it terminates quite abruptly ; inner lip spread out in a thin 



