188 CLASSIFICATION OF FISHES. 



types of their own proper circles. The snout ray s_, again, 

 are the longest^ in their bodies, oftheRaidce—ai character, 

 likewise, which more especially belongs to the northern 

 Ckimcera among the sharks; so that the analogies between 

 both become complete; and the series of affinities, in 

 which we have placed the groups, is doubly corroborated 

 by the series of analogies occurring in precisely the 

 same order. 



(166.) The rays, properly so called, is the only one of 

 all the di%'isions of the family whose types are suffi- 

 ciently made out to show a circular series ; being the 

 most typical, it is, as usual, very full of species, and me 

 variety of forms is accordingly proportionate. From 

 ignorance, however, of their manners, and of very many 

 other points in their structure (which we may hope the 

 two learned naturahsts now engaged on these fishes will 

 clear up), we cannot trace their analogies, in one instance, 

 so perfectly as could be wished ; but all the others are 

 so remarkable strong, that we have no hesitation in 

 laying the following table before the reader : — 



Analogies of the Trygonin^ and the Raid^. 



Genera of the ^ 7 • j /-.i. x families of the 



Tbygonin^. Analogical Characters. ^^^^ 



Trygon Antiq. Tail with narrow fins. TRYGOXixiE. 



Pastinaca Antiq. Tail without any fins. PrEROCEHHALijr.ii. 



Fteroplatea rkI.,H. Muzzle broad and very obtuse. Torpedin^e. 



Buia Linn. Back often armed with spines. Squatix.e. 



Aru.ar.tMs. { ^^ ^^^_ - ^P^^^ P- ] RHi.oB.a,x^ 



The division we have formerly made between those 

 sting rays which have a fin either above or below their 

 tail, and those in which all vestige of fins disappear, 

 now turns out to be precisely one of the leading discri- 

 minations between the two great divisions of the sting 

 rays, and the eagle rays ; all the latter having the ter- 

 mination of the tail quite naked. The thornbacks, and 

 the other rays, find their prototypes in Cuvier's Squatina 

 aculeatus; these groups, in fact, being the only ones 



