SOUTH AMERICAN NEMATOGNATHI. 97 



base as at tip. Fontanel extending from posterior nasal 

 openings to posterior margin of eye; a circular fontanel 

 at the base of the occipital process. 



First dorsal ray simple and its basal half as stiff as the 

 ''spines" of some species, but not separating into a 

 spinous and soft portion, higher than the following rays, 

 nearly equal to the length of the head in smaller indi- 

 viduals, one-fifth longer in the largest specimen, the rays 

 evenly and rather rapidly decreasing in height backward, 

 the last about one-third the height of the first; the tips 

 of the dorsal reaching past the origin of the adipose fin. 

 Adipose fin long, 2J-3 in the length. 



Caudal deeply emarginate; anal emarginate, the fifth 

 ray highest, lf-lf in the head. 



Ventrals large, little shorter than the head. 



Pectoral longer than the head in most of the speci- 

 mens, the outer ray not spine-like, longest, the follow- 

 ing rays rapidly shortening. 



Color light brownish, sometimes uniform, sometimes 

 with darker spots along the sides and on the adipose fin; 

 other fins plain, sometimes smutty. 



Head 4-4f ; depth 5-6; Br. 8-9; D. 7; A. 12. 



SUBFAMILY PIMELODIN^. 



DOUBTFUL SPECIES OF PIMELODINJS. 



67.1. Bagrus flavicans Castelnau, Anim. Amer. Sud, 

 Poiss. 32, pi. xiii, fig. 2, 1855 (Amazon). 



Width of body equals its depth. Head large, flat, the 

 skull not roughened; with an angle on each side behind. 

 Dorsal spine large, curved, striate but not serrate. 

 Adipose fin 9^ in the total length. Pectoral spine large, 

 curved, flattened, much longer than the dorsal spine, not 

 serrated. Maxillary barbels shorter than the head. 

 Depth 6| in the total length. D. I, 6; A. 7. Uni- 

 form light yellow. Caudal scarcely emarginate. 

 7 



