2^ tremoctopid^ — argonautidie. 



Family TREMOCTOPIDJE. 



Tremoctopus, Chiaje, 1830. 



Etym. — Tremata, pores, and Octopus. 



;S2/n.— Philoiiexis, d'Orb., 1835. 



Distr. — 6 species; Mediterranean, Atlantic, N. Pacific, Mau- 

 ritius. T. violaceus, Chiaje (xxiii, 8). 



Body rounded, head large, band of the neck very small. 

 Funnel short. Two aquiferous pores in the neck. Third right 

 arm hectocotylized, fringed on the sides, and developed in a 

 sack-like aperture on the side of the head. Two first pairs of 

 arms united by a web in the female (not in the male), other arms 

 free. 



Parasira, Steenstrup, 1861. 



Distr. — 2 sp. ; Mediterranean. P. catenulata, Fer. (xxiii, 9). 



Body rounded; head small and short; neck band rather broad; 

 Funnel long. No water-pores in the neck, two at the base of 

 the siphon. Third right arm hectocotjdized, not fringed, devel- 

 oped from a pedicelled sack. Male very different from the 

 larger female. 



The fiesh of this mollusk is tough and unwholesome, and for 

 these reasons is not sold in the Italian markets. The Genoese 

 fishermen make of the skin of the body a sort of cap, whereof 

 the reticulations serve as ornaments. 



Haliphron, Steenstrup, 1858. 



Arm only known. With bell-shaped cups, having lily-like 

 borders. 



Described from a single arm found in the stomach of a shark. 

 No species characterized. 



Family ARGONAUTIDJE. 



Argonauta, Linn., 1156. 



Argonaut, or Paper Nautilus. Argonautai. sailors of the ship 

 Argo. Syn. — Ocythoe, Leach (not Rafin.), 181*7. 



Distr. — 9 sp. All warm seas. A. A"' go (xxiv, 18 Ms found in 

 the tropical Pacific, Indian and Atlantic Oceans ; Gulf of Cali- 

 fornia, Mediterranean, Cape of Good Hope. Fossil, 2 species. 

 Tertiary of Europe. 



Characters, those of the family (p. 12). The third right arm 

 of the male is hectocotylized. 



The shell of the Argonaut is thin and translucent ; it is not 

 moulded on the body of the animal, nor is it attached by shell- 

 muscles ; and the unoccupied hollow of the spire serves as a 

 receptacle for the minute clustered eggs (xviii, 15). The shell 



