XVIII. 



CHARACTERISTIC DEEP-SEA TYPES. — MOLLUSKS. 



CEPHALOPODS. 



The shoal-water species of cephalopods, the squids and cuttle- 

 fishes, live upon the bottom ; but, being powerful swimmers, 

 they are capable of extensive migration, so that with them as 

 with fishes it will always be difficult to ascertain the depth from 



'i\>- 



Fig. 274. — Opisthoteuthis Agassizii. Abt. 5. (Verrill. ) 



which they have been obtained. Many of them are pelagic, and 

 serve as food for a large number of marine animals.^ 



Professor Verrill, who has examined the cephalopods collected 

 by the " Blake," mentions as specially noteworthy the follow- 

 ing: Opisthoteuthis Agassizii (Fig. 274), a species with a 

 broad body of a dark chocolate color, long fins, and arms united 



^ Very common in the Gulf Stream is surface. It is known as the " flying 

 the Sthenoteuthis Bartrami, large speci- squid," often darting out of the water in 

 mens of wliich are often caught on the the velocity of its movements. 



