168 



CLASSIFICATION OF FISHES. 



presence of spiracles : one may be viviparous, the other 

 oviparous — (and this deserves much investigation) ; but 

 still there will be corresponding relations, however these 

 relations may be exhibited ; and that arrangement 

 which places them in the clearest light, must always 

 be that which is nearest to Nature, 



(149-) The Raid^j or rays, succeed the sharks, to 

 which, as before remarked, they are closely and inti- 

 mately united by the savv''-fish (Pristis) : they are com- 

 posed of the rays, properly so called, having the base of 

 their tail armed with a sting, and of the torpedos, skates, 

 and thornbacks. The tAvo latter, from being well 

 known and very abundant in our own seas, will give 

 the general reader a correct idea of the whole family. 

 Taken collectively, they may be called the flat fish of 

 the cartilaginous order, and, in this respect, show a 

 marked and unquestionable analogy to that family of 

 osseous fishes. The Avhole of the species, like the sharks, 

 are marine ; and several of those found in the warmer 

 latitudes grow to a very great size. The depression of 

 their body is fully as great as what we see in the Pleu- 

 ronectidcE, or true flat fish ; but the head and eyes are 

 symmetrical ; while the pectoral fins are of such vast 

 magnitude, that they actually extent all round the head 

 and body, and terminate only at the base of the small 

 ventral fins, thus giving the body a disk-like form : the 

 tail is excessively slender ; and the dorsal fins, when 

 present, are generally remarkably small, and placed upon 

 their slender tail. In the typical species, the caudal fin 

 is mostly wanting, as the tail ends in a slender point ; 

 but in others, as the torpedo skates (^Raice) and shark 

 rays {Rhinobates), there is a small caudal, whose size 

 seems regulated by the comparative diminution of the 

 pectorals. The scapulae of the pectorals are articulated 

 with the spinal column, just behind the branchial spi- 

 racles : the eyes, and the large temporal orifice imme- 

 diately behind them, are, of course, placed on the upper 

 surface, at a considerable distance from the snout and 



