214 Panama Shells. bullion. 



impressed suture ; last whorl rather short and subangular, but 

 ventricose : aperture broadly ovate : labrum thin : labium a 

 little reflected below, above interrupted by the penult whorl. 



Mean divergence about 45° ; length .083 inch ; breadth .055 

 inch ; length of spire .045 inch. 



Operculum corneous. 



Station. — With Truncatella BairdianoL 



Habitat. — Panama ; 0. B. A. 1 



550 specimens were collected. 



This species cannot properly be referred to Truncatella. The 

 apex is not truncated ; the operculum is horny ; and the general 

 form and texture indicate a different genus. In form it approxi- 

 mates to T. fitsca, T. littorea, &o., which are not Truncatellse, but 

 which probably belong to Bemhicium. From the habits of our 

 species, it may be inferred to be an air-breathing mollusc, while 

 the characters of the shell are very different from those of 

 Bembicium. The shell appears too deficient in characters suit- 

 able for generic distinction, and we refrain from proposing a 

 new genus until the soft parts shall be known. 



Family— BULLIDJE. 

 319. Bulla (Tornatina) infrequens. Nov. sp. 



Shell cylindric, not compressed about the middle : white : 

 smooth : apex papillary, very minute and prominent : spire 

 moderately elevated, convex : whorls four and one-half, acutely 

 shouldered, with a deeply channeled suture : aperture long and 

 narrow, anteriorly rounded : labrum very thin, much advanced 

 along the middle: columella terminating in a very robust 

 spiral plait. 



Mean divergence about 130° ; length .28 inch ; breadth 11 

 inch ; length of spire .03 inch. 



Station. — Unknown. 



