^ 201. THE CEPHALOPHORA. 22.S 



Family : Tectibranchia. 



Genera : Gasteropteron, Umbrella, Doridium, Bulla, Bullaea, Aplysia, 

 Notarchus, Dolabella, Pleurobranchus, Pleurobranchaea. 



SUB-ORDER III. TUBICOLAE. 



Animals which are enclosed, together with their branchiae, in simple 

 slightly curved or irregularly flexuous tubes. 



Family : Cirribranchia. 



Genus : Deiitaliuni. 



Family : Tubulibranciiia. 



Genera : Vermetus, Magilus. 



SUB-ORDER IV. PECTINIBRANCHIA. 



Branchiae in a special cavity situated at the anterior part of the back. 

 Shell regularly spiral. 



Family: Sigaretina. 



Genus : Slgaretus. 



Family : Purpürifera. 



Genera : Buccinum, Harpa, Cassis, Purpura, Eburnea, Terebra. 



Family : Canalifera. 



Genera : Murex, Strut hiol aria, Tritonium, Turbinella, Fasciolaricu 



Family : Alata. 



Genera : Strombiis, Rostellaria, Pteroccra. 



Family : Ceritiiiacea. 



Genus : Cerithium. 



Family : Volutacea, 



Genera : Valuta, Oliva, Mitra. 



Family : Involuta, 



Genera : Cypraea, Ovula. 



Family : Conoidea. 



Genus : Conus. 

 Family : Trociioidea. 



Genera : Scalaria, Turbo, Trochus, Phasianella, Rotella, Littorina^ Jan» 



thina. 



Family : Neritacea. 

 Genera : Natica, Nerita, 



