186 



CLASSIFICATION OF FISHES. 



family now before us, is to have the snout considerably 

 elongated, and the body and tail more resembling that 

 of the true sharks, than any of the other rays ; in other 

 words, it has the head of some of the long-snouted rays 

 — such, for instance, as the Raia chayrinea * Penn. — 

 placed on the body of a shark. None of these fishes have 

 been found in the northern seas, nor are we acquaint€d 

 with any from the Mediterranean ; several, however, 

 occur in the Red Sea, and on the shores of India, of which 

 representations will be found in Rilppeirs, Russell's, 

 and Hardwick's collections of fio;ures. The sub-senus 

 Rhina probably belongs to the TorpedincB, since it has 

 the muzzle short, large, and. round, instead of length- 

 ened and pointed. 



(15"5.) The circular succession of the Raidce is thus 

 seen to be all but perfect, since the only intervals in the 

 chain occur between Sqriatina sind the two types on each 

 side of it — Torpedo and Rhinobates. It is clear that 

 RJiinohates is but the incipient form, as it were, of the 

 saw-fish ; and as these latter have always been regarded, 

 and justly, as coming within the confines of the Squalid^, 

 we must place Rhinobates as the last of the Raid^. 

 ^,Ye have no means of judging, either from specimens, 

 or a good figure and description, of the true nature 

 of the Squalus aculeatus, which Cuvier refers to the 

 Squat'incp; — Does it really belong to that genus, or to 

 a different type among the Squalidce? In either case, 

 its spined back shows its direct relation to the thornbacks 

 {Raiay, while its terminal mouth indicates the same with 

 regard to Squatina, Cestracion, &c., and the other chi- 

 ronectiform types. Under the belief, therefore, that the 

 above series is the natural one, we shall at once proceed 

 to investigate the analogies resulting from this view of 

 the Raid(E, by comparing the divisions with those of a 



* This species may be cited as an additional instance of the insufficiency 

 of arranging the car'tilajrinous, or, indeed, any other fishes, upon a primary 

 regard to thcjr teeth : for not only do these organs vary in different species, 

 and in the very same individual at different ages, but actually in the 

 sexes : the blunt tesselated teeth of the Rain chagrtnea become pointed 

 in the adult male, while in the female they never alter,— See Yarrell, vol. ii. 



p. ■ilD. 



