ANALOGIES OF THE RAlDiE. 187 



higher denomination, under which we have placed the 

 whole of the cartilaginous fishes. 



Analogies of the Rays to the Cartilaginous 

 Families. 



Sub-families of a i ■ ? r>i. ^ Families of the 



the Rays. A,ialogzcal Characters. . Cartilagines. 



Trygonince. [ "^^^"] surrounded with the pectoral j ^^^^^ 



Pterocephalince. Head distinct from the pectorals. Squalid^. 



Torpedince. [^bToicf* °^ ^^^ ''^^"^ ^^^^'^'^^'^ j Polyodonid^. 



RhinobatincB. Body much lengthened. Chim^rid^. \ 



We mustj in the first place, remind the reader of the 

 arguments already used in proof that the cartilaginous 

 orderof fishes corresponds to the natatorial order of birds, 

 where the wings are universally more developed than in 

 any other type. Now, in proof that this analogy is true, 

 we see that the pectoral fins, which correspond to the wings 

 of birds, are more developed among the rays than in the 

 sharks ; and thus we find not only that the RaidcB stand 

 at the head of the cartilaginous order, but that the 

 Trygonince, from having the pectorals so much developed 

 as to surround the snout, become pre-eminently typical 

 — and being so, are the representatives of their whole 

 family. The eagle rays and the sharks, again, stand 

 opposite each other ; and we discover an analogical cha- 

 racter, in the head of both being distinct from the pec- 

 torals. It is evident, that, in whichever family we place 

 Sqiiatina, it is analogous to the sturgeons, and to the 

 cirrated sharks ; for these are the only cartilaginous fish 

 which have cirri to their jaws ; and if Cuvier is correct, 

 that the Squalus acideatus is a Squatina, we shall have 

 another point of strong resemblance to the sturgeons, 

 which are universally armed with prickles. The broadest 

 snouts among the rays are seen in the torpedos; and the 

 broadest, as well as longest, in all the cartilaginous fami- 

 lies, is in the genus Polyodon; both being the fissirostral 



