432 FISHES 



antly in the Mediterranean, the Atlantic, the Red Sea, and the 

 Pacific. Other members of the family, referred to different 

 genera, occur in the tropical or subtropical seas all over the 

 world ; Narcine lives in the East Indies, Tasmania, China, 

 Japan, South Africa, and the Atlantic coasts of America ; 

 Discopyge in the eastern Pacific, and Hypnos in Australian 

 waters. In all the species the electric organs are present ; 

 they are situated on either side of the body between the 

 anterior prolongations of the pectoral fins and the gills. 

 These fishes in structure are similar to the common skates ; 

 they are flattened dorso-ventrally and live on the ground ; as 

 in skates, the pectoral fins are enormously enlarged and extend 

 forwards to the front of the snout, but the edges of these fins 

 are circular, not rhomboid as in the skates. 



Somewhat rudimentary electric organs also occur in the 

 skates and rays (genus Rata), but it is curious that these do 

 not correspond to the organs in Torpedo, but are placed on 

 each side of the terminal portion of the tail. 



The other fishes in which electric organs occur belong to 

 some of the more primitive families of the Order Teleostei. 

 The so-called electric eel, Gymnotus electriciis, is, as we have seen, 

 not an eel at all but is the type of the Family Gymnotidae 

 which is allied to the carps and cat-fishes or Siluroids, while the 

 eels belong to a different sub-order, the Apodes. Gymnotus 

 (Plate XXXII., C) resembles the common eel in the elongated 

 shape, in the absence of pelvic fins and in the narrow branchia 

 openings, but it differs in the entire absence of the dorsal fin and 

 the great elongation of the ventral which extends so far forward 

 that the anus is under the head. The skin is scaleless. 

 Gymnotus lives in the fresh waters of the Orinoco and 

 Amazons and reaches a large size, the maximum being placed 

 by some authorities at six feet, by others at eight. It lives 

 only in swamps, or the shallow and stagnant parts of the river- 

 systems. There are two electric organs on each side forming 

 nearly the whole substance of the tail, if we include in that 

 term all the part of the body behind the anus, that is to say 

 almost four-fifths of the length of the fish ; the upper organ is 

 large, while the lower is quite slender and runs along the base 

 of the ventral fin. 



In the Mormyridae, a family belonging to the primitive sub- 



