BULLA. ' 223 



Balla solllaria, Say, Journ. Acad. Nat. Sc. Phila. ii 245 (1822); ed. Binxey, 84.— 

 Stimpson, Check Lists, 4 (1860). 



Shell oval, rather broadest before the middle, thin, pellucid, blu- 

 ish-white ; the last whorl enveloping all the others, wrinkled length- 

 wise, and covered with minute, close, revolving lines ; the 



. r. , • • 1 11,- ,-11 Fis- 513. 



region 01 the spire is depressed, and sometimes we iind there 

 a very small opening ; aperture narrow behind, broad before ; 

 outer lip very sharp, rising in a regular curve backwards 

 above the summit of the shell ; as it ascends from below upon 

 the body of the shell it becomes a little thickened, and forms 

 a very slight fold at the umbilical region ; a very thin layer of en- 

 amel is found covering the inner margin ; umbilicus none. Length, 

 one third of an inch ; breadth, one fourth of an inch. 



Found at Martha's Vineyard, at New Bedford, and in the muddy 

 inlets in Roxbury ; Massachusetts Bay, southwards ( Stimpson) ; 

 South Carolina {Ravenel) ; Connecticut {Liiislcy). 



The differences between B. solitaria and B. iasculpla^ if there be 

 any, must be very slight. Nor do I sec that the two descriptions 

 are at all inconsistent with each other. Still, it is true that the 

 shells from Martha's Vineyard arc precisely like some from Charles- 

 ton, South Carolina, and accord with Mr. Say's solitaria ; and those 

 from Roxl)iuy are precisely like those found by Colonel Tottcn at 

 Newport, Rhode Island, and described by him. The observable 

 differences are, that the first are of a more dead white, are more 

 cylindrical, the summit has a more square appearance, the revolv- 

 mg lines are less distinct, and there is always a percei)tible opening 

 in the region of the spire. These differences may be ascribed to 

 age or locality. I have used Colonel Totten's name, since I am not 

 sure that it is the shell intended by Mr. Say. [It is now acknowl- 

 edged to be identical. 



Bulla occulta. 



Shell small, ovate-cylindrical ; spire hidden ; lip elevated above, straight in the 

 centre ; aperture rather narrow, wide below, rounded. 



Bulla occulta, Mighels and Adams, Journ. Best. Soc. iv. 54, pi. 4, fig. 11 (1842) ; Proc. 



i. .50 (1841). 

 Bulla Reinhardi, Mollee, Ind. Moll. Gr. 6 (1842) ; teste Gould, in MSS. 



Shell small, of a dingy white color, ovate-cylindrical, covered 

 with very minute, transverse strias, and with indistinct striae of 



