174 CLASSIFICATION OF FISHES. 



before which, on a line with the back, are two small 

 dorsal fins : one of these latter, or the small caudal, 

 may be expected to disappear in such aberrant species 

 as approach Pteroplatea on one side, or go off, on 

 the other, to Anacanthus Ehremb., — a genus "which is 

 stated to resemble Trygon in every thing but the 

 possession of a sting. We are thus enabled to trace 

 a circular disposition of the whole sub-family ; the 

 contents of which represent all the primary types of the 

 cartilaginous order. 



(154.) The second sub-family contains the gigantic 

 Pterocephalince* , or eagle rays. These are the fish 

 which we have already mentioned as often growing to 

 such an enormous size, and being as dangerous to man 

 as the sharks. The form of their body is much like 

 that of the s:ing rays, but with this difference. — that the 

 pectoral fins are not continued so as to encircle the fore 

 part of the head, which is consequently free; and the 

 eyes are inserted at the edge of, not within, its circum- 

 ference. The tail is as slender as in the last group, and 

 is generally armed with a formidable barb or sting at its 

 base; in addition to which, there is usually a small trian- 

 gular dorsal fin placed at the base, which is very difTerent 

 from the long and narrow fin-like membrane seen towards 

 the end of this part in many of the sting rays. Although 

 the species are by no means so numerous as in the last, 

 we yet find five divisions, so well characterised by their 

 general form, that we shall adopt them on the present 

 occasion. These gigantic fish are very rarely seen, and 

 then chiefly in warm latitudes : they seem, indeed, to 

 be pelagic, for they are seldom taken near any shore. 



(loo.) We place Myliobates as the first genus, because 

 it has a closer affinity to the typical rays than any of the 

 other four ; this is shown by its resembling Pteroplatea 

 in being much broader than long, owing to the great 



* These constitute the genus Cephaloptera of Dumeril ; but as that name, 

 unluckily, had been previously given by Geoff! Sa'mt-Hilaire to a remarkable 

 genus of birds, we propose to substitute the present for it. 



