THE STING RAYS, EAGLE RAYS, AND ELECTRIC RAYS. 33 



of them are constantly caught and brought to market in this 

 country. One of the commonest is the Thornback, so named 

 from the skin of its back being covered with a variable number 

 of thorny tubercles of singular structure. This Fish is taken 

 in abundance in the spring and summer, when it visits the shal- 

 lows for the deposition of its eggs ; and it is an excellent article 

 of food. It often attains a large size. 



582. The TRYGONID^E, or Sting Hays, have no dorsal fin ; but 

 the tail is armed with a single strong spine, notched on botlr 



sides, with which the Fish is enabled to inflict 

 severe wounds upon its captors, although it 

 does not appear that, as the ancients supposed, 

 these are of a venomous nature. The CEPHAL- 

 OPTERID^, or Fin-headed Rays, which are 

 nearly allied to the preceding, are distinguished 

 from all the other Rays by a pair of curious 

 little fins which stand out like horns from the 

 FIG. 367,-STixG-RAY. head. These Fish, one species of which is found 

 in the Mediterranean, often attain an enormous size. In the two 

 preceding families the teeth are of comparatively small size ; but 

 in the MYLIOBATID^:, or Eagle Rays, so called from the great 

 size of the pectoral fins, which not unaptly represent a pair of 

 broad wings, the jaws are covered with broad hexagonal plates. 

 In these fishes, the tail, the length and slenderness of which has 

 obtained for them the name of Whip Rays, is armed, as in the 

 Trygonidce, with a long serrated spine ; and in the Mediterranean, 

 where one of the species occurs commonly, the fishermen dread 

 this so much, that they cut off the tail of the fish as soon as pos- 

 sible after its capture. 



583. The TORPEDINID^E, or Electric Rays, of which a good 

 many species are known, are distinguished from all the other 

 rays by the rounded form and smoothness of their bodies. The 

 common Torpedo is occasionally met with on the Channel-coast 

 of England ; but it is more common in warmer seas, especially 

 the Mediterranean. Its electrical powers have been already 

 alluded to ( 562). 



584. In the RHINOBATIDJE, or Shark Rays, we meet with a 



