Bola. GANGETIC FISHES. 73 



La Cepede's arrangement appear either natural or easy ; that 

 is to say, the species included under each genus have no 

 strong general resemblance to distinguish them from those in- 

 cluded in other genera ; and there occurs the most puzzling 

 difficulty in determining what fishes have only one fin on the 

 back from those having two, and those which have the bones 

 of the head armed with spines from those which have them 

 merely indented on the edges, — the toothlets on the edges, in 

 many cases, being in fact strong spines, while all intermediate 

 degrees of strength may be observed, until, in many species, 

 the toothlets are very short and blunt. I shall here, therefore, 

 leave La Cepede as a guide, and lest a misapplication of the 

 names given by him or Bloch might mislead, I prefer a division 

 of these fishes into three genera, adopted pretty generally by 

 the Bengalese fishermen, adding to each genus a few species, 

 which these men consider as distinct, although they have a 

 strong resemblance to the fishes with which 1 have classed 

 them. 



All the fishes to which I here allude, in both jaws, have ei- 

 ther strong conical distinct sharp teeth, or many small sharp 

 teeth crowded together ; some of the bones of their heads are 

 distinctly indented on the edges ; some of their fins are armed 

 with prickles ; and each of their ventral fins contains six rays. 



VI. Genus. — Bola. 



Fishes of the fourth order with strong distinct sharp teeth in 

 each jaw ; with some of the bones in the head indented on the 

 edge ; with prickles in some of the fins, and six rays in each 

 ventral ; and with opaque bodies compressed to a ridge on the 

 back, but widening gradually towards the belly, so that a trans- 

 verse section at the shoulders is somewhat triangular. 



The fishes of this kind afford a very light, easy digested ali- 



