SHALLOW-WATER FAUNA. 37 



ever, is not directly associated with their mode 

 of life, but may " be briefly referred to here 

 whilst dealing with the family. This is the 

 electric organ. In the younger stages of the 

 common English Skate a small region of the 

 muscular system on each side of the base of the 

 tail becomes changed into an electric organ, but 

 the discharges which it is able to give are so 

 feeble that they can only be appreciated by a 

 galvanometer. In the Torpedo, however, the 

 electric organs are very large indeed, and situated 

 one on each side of the head. They can give a 

 shock which is powerful enough to kill small 

 animals and to stun larger ones. With such a 

 formidable weapon of offence and defence, it is 

 clear that the need for active movements is 

 considerably diminished, and the Torpedoes are 

 described as being exceedingly slow in pro- 

 gression and incapable of the violent movements 

 of other Skates. 



The other Flat Fishes found on sandy bottoms 

 belong to a different group altogether, and are 

 characterised by their bony skeletons and other 

 features. The 

 Soles and their 

 allies do not, 

 like the Skates, 

 lie flat upon 

 their bellies, 



but are lateTCllll/ FIG. 9. The Common Sole, showing both eyes 

 Compressed on one side of the head. 



and lie upon one side. The side which is 

 habitually uppermost is of the colour of the 

 sand, and the other almost invariably pure white. 



