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, 2|-3 in the length. 



Caudal deeply emarginate; anal emarginate, the fifth 

 ray highest, 1-|-1| 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. 



Head4-4f; depth 5-6; Br. 8-9; D. 7; A. 12. 



Subfamily PIMELODINaE. 



DOUBTFUL SPECIES OF PIMELODINJi:. 



67.1. Bagrus Jiavicans 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. 

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