44 MARVELS OF FISH LIFE 



when divided with a knife down the back from the 

 snout to the tip of the tail, the two halves are similar 

 in their structure, and in the organs they contain, the 

 wing-like fins on either sides being the modified pectoral 

 fins, which have extended along each border. 



The flat fish, on the other hand, has been flattened 

 from side to side, so that when divided in a similar 

 manner the back with its muscles would be in one half, 

 and the organs of digestion in the other half. Later, 

 when considering the plaice, we shall see how this fish 

 starts life as a rounded larva, then becomes flat, and 

 falls over on its side. 



Flattening and coloration are not the only means of 

 assisting the ray in the struggle for existence. The 

 sting-ray is armed with a murderous barb, near the end 

 of the tail, with which he is able to inflict a terrible 

 wound ; the torpedo ray is able to paralyse fishes by 

 giving them an electric shock, and all rays possess sharp 

 spines on their backs. The thornback ray is particularly 

 well armed with these spines, hence its name. 



