GENERA OF SHELLS. @[ 



ACERA. No shell. 



BULL^EANA. 



BULLJEA. 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 

 whole 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. haliotidea. 



