164 INVERTEBRATA OF MASSACHUSETTS. 



State Coll., No. 117. Soc. Cab., No. 2384. 



Bulla Gouldii, Couthouy; Bost. Journ. JVal. Hist., ii. 181, pi. 4, f G. 



Shell small, ovate, shining, of a dead white color, covered with 

 a yellowish epidermis ; whorls four, rounded at their upper edges, 

 their dividing line well marked ; the last whorl is as long as the 

 shell, and includes all the others ; under the magnifier its surface 

 appears covered with revolving lines ; the whorls all rise to about 

 the same level, so that the summit is nearly fiat ; the anterior ex- 

 tremity is rather narrower than the posterior ; the aperture is nar- 

 row behind, and suddenly enlarged by the curvature of the inner 

 margin, which is a little thickened, white, and polished. The 

 outer lip, from its junction behind, advances a little as it turns for- 

 ward by a regular curve, and, finally turning backward by a rather 

 sharp turn, it joins the body of the shell with a gentle twist ; um- 

 bilicus none. Length -^\ inches, breadth 2V hich. 



Found by Mr. Couthouy in the stomachs of fishes, taken off 

 Cohasset Rocks, and dredged by Col. Totten in Provincetown 

 harbour. 



Li shape it somewhat resembles B. solilaria ; but it is a smaller and 

 much more solid shell, and its flat summit, with the display of all its 

 whorls there, plainly distinguishes it. The anterior extremity is also 

 more pointed. It is much broader and less cylindrical than B. canalicu- 

 lata, nor has it the conspicuous fold on the pillar, as that shell has. 



Bulla de'bilis. 



Shell ohliqiiehj ovate, small, transparent, inflated, smooth, par- 

 tially umbilicated ; %vhorls four, terminating on a level; pillar 

 lip terminating abruptly in front. 



Figure 95. 



State Coll., No. 112. Soc. Cab., No. 2388. 



Bulla debilis, Gould ; SilliTnan's Journ., xxxviii. 196. 



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 length 

 of the shell, including all the others, and partially detached from 

 them above ; surface without apparent marks ; aperture as long as 



