28 CATALOGUE OF CEPHALOPODA. 



of length, 2, 1, 3, 4 ; two dorsal pairs flattened, and webbed to 

 the tip. 



Octopus velifer Feruss. Poulpes, t. 18, 19. 1830; Verany, Cat. 



1829. 

 Tremoctopus violaceus Delle Chiaje, MS. 1835 ; Verany, Cat. 



1829. 

 Octopus violaceus Feruss. Pordpes, t. 20. from Chiaje. 

 Octopus velatus Rang, Mag. de Zool. p. 60. 1837. 

 Philonexis velifer UOrb.Mon. Ceph. Acet. 91., Poulpes, 18, 19, 



20. 23. 29. 1838, Moll. Viv. et Fos. i. 205. t. 5. f. 7. 1845. 

 Phisoniscus velatus Riippell, MS. Brit. Mus. 

 Ocythoe mygaro Risso, Fur. Merid. 



Hab, Mediterranean. 



a. Messina. Adult. In spirits. Dr. RiippelTs Collection. 



Fam. III. OCYTHOID^E (ARGONAUTID.E?). 



Body ovoid, enlarged in front, smooth, covered with a thin skin 

 marked with chromatic glands. Ventral aperture extending 

 to under the eyes. Cervical band moderate. Ventral part of the 

 mantle supported by an elevated button on the inner side near 

 the margin, fitting into a notch at the base of the siphuncle. 



Head oblique, short above and long below. Eyes lateral, very 

 large, ovate, prominent, covered on the upper edge with a very 

 thin eyelid. Beak broad, not compressed. Ear small, behind 

 the eye, under the cervical band and lateral aquiferous opening. 

 Aquiferous openings one pair at the upper hinder angle of the 

 eye. 



Arms tapering, very unequal ; the dorsal pair bent back on them- 

 selves and furnished with a membrane, the lower pair with a 

 broad membranous exterior keel, the lateral pairs depressed. 

 Cups in two series, prominent, as if slightly pediceled. 



Siphuncle very large, conical, attached by two exterior lateral and 

 two other medial very thin bands. 



? Shell (Argonauta) exterior, one-celled, thin, brittle, transparent, 

 horny, calcareous, slightly flexible when wet ; nucleus hemi- 

 spherical, very large. 



The female Ocythoes are often found in the shell of the Argo- 

 naut, and have hence been supposed to form these shells, and as 

 yet no other animal has been found inhabiting them ; but there 

 are several reasons for believing that the Ocythoe is only a parasite 

 adapted by its form to live in such shells, as the web of the arms is 

 used by the animal to embrace the shell and keep it in its right 



