172 CLASSIFICATION OF FISHES. 



and so firmly is this believed by fishermen^ that upon 

 catching any of these sting rays, they immediately pro- 

 ceed to cut off the tail of the fish_, or mutilate the spine. 

 The use of the long naked taih seen in most of these 

 fish, is probably to twine round their prey_, so as to con- 

 fine its stru2;2:les. Sometimes there are tvro of these 

 barbs placed close together ; but in some of the sub- 

 genera^ both are absent. 



(153.) The first, or typical, sub-family, containing 

 the true rays, is eminently distinguished from all the 

 others, by the pectoral fins being united to the snout 

 in such a manner as that there is no interval of separa- 

 tion between them. All our British species^ including 

 the thornbacks, skates, &c., are of this description, and 

 afford perfect examples of the general form pervading 

 the whole of this division : in other respects, there are 

 many variations. The group, indeed, is so numerous in 

 its contents, that we may even distinguish the genera, 

 which we shall now enumerate. The trygons, or sting 

 rays (^Trygon Antiq.), divide themselves into three 

 genera. The first is Trygon, where the breadth of the 

 body and pectorals is about equal to its length : the tail 

 is armed with one or two spines, or stings, as they are 

 called, at the base ; and there is a narrow fin, either 

 above, or below, or on both sides. Pastinaca Antiq. * 

 differs from Trygon only in having the tail entirely 

 naked : the common sting ray of the Mediterranean is 

 the type of this genus, to which we prefer retaining the 

 name by which it was known to the ancients. In two 

 others, described and figured as natives of the Indian 

 seas by Dr. Russell, the body is somewhat more oval 

 than in the Mediterranean species, and there are two 

 spines ; but the number of these do not appear to in- 

 dicate generic groups ; and it not unfrequently happens 

 that, in such as really possess two spines, one is acci- 

 dentally broken off. The presence or absence of fins 



* Himanturat Muller and Henle. 



