136 CEPHALOPODA. 



to time worm-like creatures, called Hectocotyli, 

 wliicli have been supposed to be parasitic worms. 

 They resemble single detached arms of the species, 

 being armed with rows of suckers, and adhere to 

 the interior of the gill-cavity of the female. Dr. 

 Kolliker first suggested that these supposed worms 

 were the males ; but, from the researches of H. 

 Miiller and others, it appears that the Hectoco- 

 tylus is not an independent animal, but " an arm 

 metamorphosed in a very irregular manner," and 

 detached, in order to play an apparently inde- 

 pendent part in impregnating the female.* 



The eggs are laid in masses, enclosed in en- 

 velopes, by which they are bound together, and 

 often attached to rocks or sea- weeds, or else are 

 united into chaplets which float in the open sea. 

 The young are hatched in the form of the parent, 

 so that they undergo no metamorphosis. 



Localities, &c, — All our species are residents of 

 the deep water. Sometimes they may be found 

 in pools at low water, left by the retiring tide, and 

 occasionally specimens are washed up on a sandy 

 beach ; but generally they are free swimmers and 

 rovers, often congregating in shoals. Their period 

 of activity is chiefly nocturnal. The little Sejpiola 

 burrows in sand, which it excavates in a curious 

 manner by blowing repeated gusts of water out of 

 its funnel. t All the species are carnivorous and 

 ferocious, preying on any marine animals which 

 they can master. 



Identification. — The number of the arms ; the 

 presence of accessory tentacles ; the eyes, whether 



* See Siebold's Comp. Anat. § 261. (Burnet's Transl. and note.) 

 f See my " Aquarium," p. 69. 



