206 CUTTLE FISH. 



shells, the inhabitants of which pass their entire life in the 

 sea far away from any shelter except that afforded by the 

 floating Gulf-weed, and whose organization is peculi- 

 ary adapted to that sphere of existence. In appearance 

 they strikingly resemble the fry of the ordinary sea-snails, 

 swimming, like them, by the vigorous flapping of a pair of 

 fins. To the naturalist on shore they are almost unknown, 

 but the voyager on the great ocean meets them where 

 there is little else to arrest his attention, and marvels at 

 their delicate forms and almost incredible numbers. They 

 swarm in the tropical, and no less the Arctic seas, where by 

 their myriads, the water is discolored by them for leagues. 

 They are seen swimming on the surface in the heat of the 

 day, as well as in the cool of the evening. In high latitudes 

 they are the principal food of the whale and of many sea- 

 birds. 



Another floating inhabitant of the deep is described as the 

 beautiful lanthina or Ocean-Snail, which is quite blind, and 

 has large horny jaws, furnished with sharp, curved, slender 

 teeth. This animal is remarkable for floating shell down- 

 wards in the water, and the anterior part of the foot forms 

 a shallow cup, which embraces the smooth anterior rounded 

 part of the float. Thus the fish can raise or lower itself in 

 the water at pleasure. When it wishes to bring its head to 

 the surface of the water, this part of the foot is made to 

 glide over the back of the float. The floats are made of a 

 mucous film containing air ; and when cut with scissors, the 

 animal descended to the bottom of the vessel in which it 

 was consigned, and did not make a new one. 



The nautili belong to a class called Cephalopoda, so 

 named from the singular attachment of the feet to the head 

 — locomotive organs employed as oars or feet when moving 

 along the bottom of the sea, and consisting of a circlet of 

 muscular arms or tentacles, in addition to which many of 

 this class have fins. To this same definition of Linnaeus 



