290 



CHARACTERS OF VERTEBRATE ANIMALS 



head. The slender tail is usually armed with a formidable saw- 

 edged spine, which is the so-called " sting ". One widely distri- 

 buted species, the Common Sting- Ray {Trygon pastinacd), is 

 sometimes caught off the south of England. 



5. Electric Rays. — In these the broad smooth body has a 

 rounded outline, and on each side of the head there is an electric 

 organ, capable of giving severe shocks. The most familiar genus. 

 Torpedo, is represented by species in the Atlantic, Mediterranean, 

 and Indian Oceans. A well-known Mediterranean form is the 

 Marbled Torpedo {Torpedo marmorata), and an allied species is 

 taken from time to time in British seas. 



Sub-class IV.— CHIM^ERAS (Holocephali) (fig. 168) 



This small sub-class, though related in many ways to the 

 preceding one, is distinguished by a number of peculiarities. 

 It includes only three genera of deep-water fishes. The best- 



■DO.RSAL FINS 



Fig. 168. — Chimaeroids, reduced to various scales 

 A, Sea-Cat [Chimara moitstrosa), male, n, Bottle-nosed Chimaera {Callorhynchics antarcticus). C. Harriotia. 



known form is the Sea-Cat or " King of the Herrings" {Ckimcera 

 monstrosd), the distribution of which includes the North 

 Atlantic, Mediterranean, Cape of Good Hope, and Japan. In 

 this animal the large head is rounded and the tail tapers to a 

 mere thread. There is a powerful spine in front of the first 

 dorsal fin, while in the male there is a peculiar tentacle-like 



