22 TREMOCTOPIDA—ARGONAUTID &®. 
Famity TREMOCTOPID &. 
TreMmoctopus, Chiaje, 1830. 
Etym.— Tremata, pores, and Octopus. 
Syn.—Philonexis, d’Orb., 1835. 
Distr.—6 species; Mediterranean, Atlantic, N. Pacific, Mau- 
ritius. TZ. 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 
imee: 
; PARASIRA, Steenstrup, 1861. 
Disir.—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 hectocotylized, not fringed, devel- 
oped from a pedicelled sack. Male very different from the 
larger female. 
The flesh 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 
tbe 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. 
Famity ARGONAUTID #. 
ArGonauta, Linn., 1756. 
Argonaut, or Paper Nautilus. Argonautazi, sailors of the ship 
Argo. Syn.—Ocythoé, Leach (not Rafin.), 1817. 
Distr.—9 sp. All warm seas. A. Argo (xxiv, 18) is found in 
the tropical Pacific, Indian and Atlantic Oceans; Gulf of Cali- 
fornia, Mediterranean, Cape of Good Hope. Fosszl, 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 
