36 CATALOGUE OF CEPHALOPODA. 



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

 Cuba, i. 7. 1841) thus : 



i. Myopsidm Eyes covered with the skin, without immediate 

 contact with the water: this will contain Cranchiadm, Sepiada, 

 Spindidce, and Loligidce. 



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

 the water: Loligopsida, Chiroteuihida, Onychoteuthidm, and 

 Belemnitidce. 



Synopsis of Families. 

 A. Shell solid, horny. — Chondbophoba. 



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



pidae.) 



I. Crancmadje. Eyes covered with the skin. Siphuncle 



with a valve. 

 II. Loligopsidaz. Eyes naked. Siphuncle simple. 



33. Mantle furnished with three internal Cartilages; one dorsal, two 



ventral. 



III. Chiroteuthidje. Eyes naked, simple above. Siphuncle 



simple. 



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



phuncle with a valve. 

 V. Loligidm. Eyes covered with skin, simple. 



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



on ventral side. — Sepiaphoba. 



VI. Sepiadje. Eyes covered with skin. Head united to mantle 

 by a broad cervical band. 



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



NOPHOBA. 



VII. Spirulidm. Shell spiral, whorls separate. 

 VIII. Belemxitidas. Shell straight. 



