470 



PROCEEDINGS OF THE ACADEMY OF 



[Oct., 



convexly rounded. Edges of caudal peduncle above and below convex. 

 Head robust, well compressed. Snout broad with convex surface. 

 Lips fleshy. Teeth large, triangularly cuneate, yl^, and more or less 

 directed backwards. In upper jaw each one with one or more basal 

 cusps, but of mandibulars only symphyseal one with an approxi- 

 mated cusp. Mandibular teeth longer than those above, though of 

 uniform size. Folds of buccal cavity thick and fleshy, more 



Fig. 53. — Serrasalmus cosopus (Cope). 



or less papillose and with cutaneous fringe corresponding to 

 teeth. Palatine teeth 5, small and uniserial. Tongue little free, 

 surface papillose. Interorbital space broad and convex. Gill-open- 

 ing forward to front rim of pupil. Rakers 14 + 12, more or less 

 rudimentary, or about 5 or 6 on ceratobranchial a little enlarged, 

 and all much shorter than filaments which are nearly equal to orbit. 

 Tubes a little bifurcate, or decurved usually. Vent close in front of 



