68 MANUAL OF THE MOLLUSCA. 



The only known species, P. cordiformis, was discovered by MISI. Quoy 

 and Gaimard, on the coast of New Zealand ; it exceeds 3 feet in length. 



Eledone. (Ai-istotle.) Leach. 

 Type, E, octopodia, L. 



Suckers forming a single series on each arm ; length 6 to 18 inches. E. 

 moschata emits a, musky smell. 



Bistr., 2 sp. Coasts of Norway, Britain, and the Mediterranean. 



CiRROTEUTHis, Eschricht. 1836. 



JEii/m., cirrus, a filament, and teuthis a cuttle-fish. 



Body with two transverse fins ; arms united by a web, nearly to their 

 tips ; suckers in a single row, alternating with cirri. Length 10 inches. 

 Colour violet. The only species (C. Millleri Esch.) inhabits the coast of 

 Greenland. 



Philonexis, D'Orb. 



Etym., philos, an adept in nexisy swimming. 



Type, P. atlanticus, D'Orb. 



Arms free ; suckers in two rows ; mantle supported by two ridges on the 

 funnel. Total length, 1 to 3 inches. 



Bistr., 6 sp. Atlantic and Medit. Gregarious in the open sea ; feeding 

 on floating molhisca. 



Sxih-genus. Tremociopus (Chiaje), pi. I., fig. 3. 

 Name from two large aquiferous pores {tremata) on the back of the head. 

 Arms partly, or aU webbed half-way up, 

 Bistr., 2 sp. T. quoyanus and violaceus. Atlantic and Medit. 



SECTION B. Decapoda. 



Arms 8. Tentacles 2, elongated, cylindrical, with expanded ends. Suckers 

 pedunculated, armed with a horny ring. Mouth smTounded by a buccal 

 membrane, sometimes lobed and funished with suckers. Eyes moveable in 

 their orbits. Body oblong or elongated, always provided with a pair of fins. 

 Funnel usually furnished with an internal valve. Oviduct single. Nidamental 

 gland lai'gely developed. Shell internal ; lodged loosely in the middle of the 

 dorsal aspect of the mantle. 



The arms of the decapods are comparatively shorter than those of the 

 octopods ; the dorsal pair is usually shortest, the ventral longest. The tenta- 

 cles originate within the circle of the arms, between the third and fourth pairs; 

 they are usually much longer than the arms, and in cheiroteuthis are six times 

 as long as the animal itself. They are completely retractile into large sub- 

 ocular pouches in sepna, sepiola, and rossia ; partly retractile in loligo and 

 sepioteuthis ; non -retractile in cheiroteuthis. They serve to seize prey which 

 may be beyond the reach of the ordinaiy arms, or to moor the animal in 

 safety during the agitation of a stormy sea. 



