196 ANIMALS OF THE SEASHORE 



foot is partly fused with the head above the eyes 

 and around the mouth. 



Except for the Nautilus and one or two others, 

 the animals of this group do not possess an external 

 shell. The shell is internal and very much modified. 

 The common squid (Loligo pealei) has a horny struct- 

 ure known as the pen which is really a modified inter- 

 nal shell. The Squid of the Mediterranean (Sepia) 

 has a hard pen known as the cuttle bone, of which 

 the canary birds are so fond. 



In former geological ages, Cephalopods were 

 much more abundant than at present and their 

 fossil remains are often abundant in the rocks. Many 

 reached a great size, either elongate such as the 

 modern squid, or coiled like the Nautilus. Pens of 

 BellemnitelJa americana are abundant in the Cretace- 

 ous deposits of New Jersey and elsewhere on the 

 Southern Atlantic Coastal Plain. 



Loligo pealei Leseur (Squid) 



Fig. 33 



Body cylindrical, about 8 inches long, tapering 

 to a point; terminal fins about half as long as the 

 body. The internal shell or pen is as long as the 

 main part of the animal; conspicuous eyes equipped 

 with a cornea. 



The squid resembles a submarine boat. Its 

 method of locomotion is rather unique. It squirts 

 a stream of water from a little tube near its neck; 

 if it squirts forward, the animal moves backward. 

 The squid, therefore, is the Rocket Animal of the 



