BULLA. 223 



Bulla solllaria. Say, Journ. Acad. Nat. Sc. Phila. ii 245 (1822); ed. Binney, 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, wrinlcled length- 

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

 region of the spire is depressed, and sometimes we find 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 (^Lirisley). 



The differences between B. soHtaria and B. insculpta, if there be 

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

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

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

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

 from Roxbury are precisely like those found by Colonel Totten 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- 

 ing lines are less distinct, and there is always a perceptible 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-cyUndrical ; spire hidden ; lip elevated above, straight in the 

 centre ; aperture rather narrow, wide below, rounded. 



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



i. .50 (1841). 

 Bulla Rcinhardi, Moller, 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 



