208 



CLASSIFICATION OF FISHES. 



more so in the present case^ because it gives a sanction, 

 in some sort^, to the conclusion we have almost come to, 

 that this idea of its relations is founded in nature, and 

 that Polypterus, in reahty, may ultimately prove the re- 

 presentation of that fifth type of the PlectognatheSy 

 which we have long been searching after. Limited as is 

 our space, the structure of this fish is so remarkable, that 

 it must not be hastily passed over ; the annexed figure of 

 P.Niloticus(^fig.SQ.), aided by the following description. 



-^^' is4'HSr'r tiAeiaiit r 



abridged from M. Geoffroy's own account, are therefore 

 placed before the reader. The usual length of the Nilotic 

 Polypterus is about eighteen inches, and its colour is sea 

 green, paler beneath, and marked with irregular black 

 spots : it bears some resemblance to certain genera in 

 the Esox, or pike family, by the shape of its body, &c. ; 

 but these seem to be very distant. The shape is long and 

 anguilliform — the body being nearly cylindrical: the head 

 is defended by large bony plates (^fig. 37-) i ^^^ ^^^ body 



covered, or rather mailed, with large strong scales of a 

 stony hardness, and so firmly attached to the skin that 

 it is hardly possible to open the fish with a knife ; so 

 that the natives only draw off the skin whole, after the 

 fish has been boiled. The pectoral and ventral fins, 

 but particularly the former, are attached by a sort of 



