36 CATALOGUE OF CEPHALOPODA. 



M. D'Orbigny separates this order into two suborders (Moll. 

 Cuba, i. 7. 1841) thus : 



i. MyopsidcB Eyes covered with the skin, without immediate 

 contact with the water: this will contain CrancMadce, Sepiadcs, 

 SpirulidcB, and Loligidce. 



ii. Oigopsidce. Eyes open externally, in immediate contact with 

 the water : Loligopsidce, Chiroteuihidce, Onychoteuthid(B, and 

 Selemnitidce. 



Synopsis of Families. 

 A. Shell solid, horny. — Choxdrophora. 



^, Mantle supported by two internal fleshy Bands. (Allied to Octo- 



pidae.) 



I. Cranchiadx. Eyes covered with the skin. Siphuncle 

 with a valve. 



II. LoLiGOPSiDM. Eyes naked. Siphuncle simple. 



28. Mantle furnished tvith three internal Cartilages; one dorsal, two 



ventral. 



III. Chiroteuthidm. Eyes naked, simple above. Siphuncle 



simple. 



IV. Onychoteuthid.e. Eyes naked, with a sinus above. Si- 



phuncle with a valve. 



V. LOLIGIBM. Eyes covered with skin, simple. 



B. Shell cellular, calcareous. Mantle with two cartilaginous Ridges 



on ventral side. — Sepi aphora. 



VI. Sepi ADM. Eyes covered with skin. Head united to mantle 

 by a broad cervical band. 



C. Shell chambered, siphoned, calcareous or horny. — Belem- 



KOPHORA. 



VII. Spirulidje. Shell spiral, whorls separate. 

 VIII. Belemnitid^. Shell straight. 



