SILUBID^. 



THE PIMELODIN^. 



339 



of M. Cuvier's divisions (or sub-genera^ as they are 

 termed) Pimelodus and Bagrus, — two artificial groups, 

 which we have found it impossible to understand : to 

 us they appear to be common receptacles for all Silurt 

 having two dorsal fins. Commencing, then, our survey 

 with &uch Pimelodir as seem to have the greatest 

 affinity with the last sub-family, we may notice the 

 genus Synodontes, where the head is mailed as far as the 

 first dorsal fin ; but the body is entirely naked ; the 

 muzzle is naked and unusually narrow ; while the 

 lower jaw is armed with numerous hooked flexible 

 teeth, of a structure altogether unique, as M. Cuvier 

 observes, among fishes : it would appear, however, that 

 this is not strictly the case, for the teeth of Hypostoma 

 etentaculum of Spix are similarly formed ; while they 

 are, no doubt, articulated or flexible at their roots, in 

 the same way as in Synodontes ; otherwise they would 

 be useless, as the hooks at their end could not act. 

 Close to this type, well represented by ^yn. Ruppelli 

 {Jig. 82.), Cuvier places Lacepede's genus Agenieosus^ , 



founded on the military or horned siiure of Bloch 

 (pi. 262.), and with which he associates the Pimelodus Si- 

 londia of Hamilton (pi. 9- f- 50.) ; but as both these 

 fishes have the belly much shorter than the tail, they do 



* Ageniosus of our Synopsis. 

 Z 2 



