XU LIST OP PLATES. 



2. Achatina acicida. Achatina 1ms a notch at tlie end of tlie 



columella, thus differing from JBulimus. 



3. Testacella Haliotoidea ; a slug, with a small shell at its back. 



4. Helix pomatia ; a large snail. 



5 . Cyclostoma elegans ; a land-shell with an operculum. 



6. Succinea putris. 



7 a. Aplyda hyhrida, with the shell entirely enveloped. 

 7 b. Shell of the same. 



Plate XX. 

 WATER-SNAILS. 

 1. PJiysa hypnorum. 

 3. LimticBus stagnalis. 



3. Flanorhh vortex. 



4. Ancylus Jluviatilis ; the animal resembling those of Physa and 



Limnceiis, notwithstanding the difference of the shells. 



CEPHALOPODA, OR CUTTLE-FISH. 



5. Rossia macrosoma. 



6. Internal bone or shell of the Sepia officinalis. 



