ANALOGIES OP THE SALMON. 



257 



is smooth ; but then the 

 teeth of the jaws are large, 

 trjangular_, cuttings and 

 dentated : in some, in- 

 deedj as mMyletes Cuv., 

 the teeth are so strong as 

 to be employed in mas- 

 tication. The form, num- 

 ber, and situation of these 

 teeth vary in a remarkable 

 manner ; but, from being 

 present in all the species 

 and sub-genera, we may 

 at once decide that the 

 Serrasalmi are the most perfectly dentated of the 

 American division, just as the true salmons are of 

 such as occur in Europe. The affinity between Ser- 

 rasalmo and Characinus (Jig, 52. a) is as intimate, ac- 

 cording to the way in which Cuvier has placed them in 

 his system, as that which unites Salmo with Coregonus : 

 now^ the teeth in both these groups are always smaller 

 and fewer than in the two preceding ; they have both 

 a small mouth ; the scales of both are larger ; and in 

 both, the teeth are often altogether wanting : this re- 

 semblance, in fact, between the two is so strong, that 

 we might almost think they were united by affinity, 

 because it will be remembered that the different types 

 of Characinus are the only fishes among the American 

 salmon which have the anal fin short. There is, how- 

 ever, a peculiar aspect about these latter, by which the 

 practical ichthyologist will readily detect them, inde- 

 pendent of their geographic range, and the remarkable 

 difference in the number of the rays to the gills. In 

 Coregonus, these rays amount to seven or eight ; but in 

 CharacinuSj and all the American salmon, they do not 

 exceed, according to the best authorities*, more than 

 four or five ; nor have the American fishes any teeth 



* Artedi, Cuvier, Bloch : the former chiefly founded the genus on 

 this very peculiarity. 



VOL. I. S 



