68 MANUAL OF THE MOLLUSCA. 



The only kuown species, P. cordiformis, was discovered by ;MM. Quoy 

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



Eledone. (Aristotle.) Leach. 

 Ti/pe, E. octopodia, L. 



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

 moschata emits a musky smell. 



Distr., 2 sp. Coasts of Norway, Britain, and the ]Mediterranean. 



CiRROTEUTHis, Eschricht. 1836, 



Etym.^ cirrus, a filament, and teuthis a cuttle-fish. 



Bodi/ with two transverse fins ; artns 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. Miilleri Esch.) inhabits the coast of 

 Greenland. 



Philonexis, D'Orb, I 



Etym., pJiilos, an adept in nexis, 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. 



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

 on floating molhisca. 



Sub-genus. Tremoctopus (Chiaje), pi. I., fig. 3. 

 Naine from two lai-ge aquiferous pores {treinata) on the back of the head. 

 Arms partly, or all webbed half-way up. 

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



SECTION B. Decapoda. 



Arms 8: Tentacles 2, elongated, cylindi'ical, viith expanded ends. Suckers 

 pedunculated, armed with a horny ring. Mouth surrounded 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 ai-e 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 sepia, sepiola, and rossia ; partly retractile in loligo and 

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

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

 safety during the agitation of a stormy sea. 



