GENERA OF SHELLS. Qi 



AcERA. No shell. 



BULLiEANA. 

 BuLL^A. Shell very thin, partially convo- 

 luted, and spiral at one side, without columella 

 or spire ; aperture very large, patulous above. 



B. aperta. 



Bulla. Shell ovate globose, convolute, no 

 columella nor projecting spire ; aperture the 

 v^^hole length ; right margin sharp. 



B. lignaria, ampulla, striata, naucum, physis, fasciata, 

 aplustre, hydatis, cornea, fragilis, solida, — solitaria. 



LAPLYSIANA. 

 Laplysia. Shield dorsal, semicircular, sub- 

 cartilaginous. 



L. depilans, fasciata, punctata, radiata. 



DoLABELLA. Shell oblong, subarcuate, 

 hatchet-shaped : contracted, thick, callous and 

 nearly spiral at one side ; the other broader, 

 flatter and thinner. 



D. Rumphii. fragilis. 



LIMACIANA. 

 Onchidium. No shell. 



Parmacella. No described shell. 



LiMAx. A coriaceous shield. 



Testacella. Shell minute, external, sub- 

 auriform, apex obsoletely spiral ; aperture very 

 large, oval, obliquely dilated ; left lip involute. 



T. kaliotidea. 



