1 68 Apodal Fishes of Bengal, 



torals. In the second, that organ begins to lose a portion 

 of its importance, and its connection with the anal by means 

 of the caudal fin, becomes interrupted and broken off. This 

 change exercises an important influence over the habits of 

 these animals, and introduces another family, Ophisuridae, of 

 less rapacious habits than the last. 



It is composed of species which, from the absence of the 

 caudal fin, are less capable of making the violent and sud- 

 den spring essential to the more rapacious kinds, and for 

 which they are so well adapted. 



Nothing can be more simple and complete than the tran- 

 sition by which nature passes here from one extreme to 

 another, in the organization and functions of animals. 



The change from Anguilldce to Ophisuridce ', where these 

 families approach each other by means of Murcenesox and 

 Leptognathus, affords an interesting instance of the ease 

 with which the most opposite characters become blended 

 together in the works of nature. The essential character of 

 the family to which Leptognathus belongs, consists in the 

 want of a caudal fin, but as it is still necessary to retain 

 some function of the preceding genus to which its structure 

 is allied, the extremities of the anal and dorsal are rendered 

 broad and dilated, so as to compensate in this species for 

 the imperfections of the family to which it belongs. 



Passing through the Ophisuridce, we find the pectoral fins 

 begin to diminish in size until they become barely percep- 

 tible as in Sphagebranchus imberbis, and some other species 

 of which we make the proposed genus Ophithorax. These 

 last form a natural transition to the Murcenidce, in which there 

 are no pectoral fins whatever. 



The first genus of Murcenidcc affords some species 

 evincing an affinity to the preceding family, by the absence 

 of the caudal fin ; and one of them, Dalophis, which leads 

 us back again to the ordinary type, presents a repeti- 

 tion of the increased development at the end of the dorsal 



