BRITISH MARINE TESTACEOUS MOLLUSCA: 



Third Division. 



fLATERIBRANCHIATA. 

 GASTEROPODA^ CYCLOBRANCHIATA. 

 LCERVICOBRANCHIATA. 



Hermaphrodita, sine congressu. 



* Lateribranchiata. 

 DENTALIAD^E .................... Dentalium. 



** Cyclobranchiata. 

 CHITONID.E ...................... Chiton. 



*** Cervicobranchiata. 

 PATELLID.E ...................... Patella. 



Acmaea. 



Pileopsis. 



Calyptrsea. 



Emarginula. 



Fissurella. 



Puncturella. 



Haliotis. 



Eourth Division. 



rPLEUROBRANCHIATA. 



CRYPTIBRANCHIATA. 

 GASTEROPODA^ 



I PULMONIFERA. 



LPARS-PECTINIBRANCHIATA. 



Hermaphrodita, congressu . 



* Pleurobranchiata. 

 PLEUROBRANCHID^: ................ Pleurobranchus. 



** Cryptibranchiata. 

 APLYSIAD^: ...................... Aplysia. 



Bulla. 



Bullsea. 



Otina? 



