528 PROCEEDINGS OF THE ACADEMY OF [Jl^lly, 



Form moderately elongate. Snout moderate, 3 in head. Upper 

 profile slightly concave from tip of snout to apex of occipital process; 

 slightly convex from there to the origin of the dorsal. Profile of belly 

 almost straight from origin of pectorals to origin of anal. 



Scales moderate, very regularly arranged. 



Palatines each with a single series of strong conical teeth, those in 

 front larger than the others; premaxillaries, maxillaries and mandible 

 each with a single series of conical teeth; two canines in each inter- 

 maxillary, one at the front end and the other f the way back. Maxillary 

 not covered by the preopercle. No canines in the maxillary, the teeth 

 pointing backward and largest about the middle of the series. Man- 

 dible heavy, tapering rapidly to the point; its rami close but not touch- 

 ing along the under side. Four canines in each side of the mandible, 

 a large one on each side in front; a moderate-sized canine about mid- 

 way of the mandible, and between them two small canines on each side; 

 back of each posterior canine a single series of fine conical teeth; no 

 fine teeth between the canines. 



Gill-rakers moderate, setiform. Eye large, 4 in head. Preorbital 

 narrow. Suborbitals broad. 



Origin of dorsal half-way between tip of snout and tip of the middle 

 caudal rays; its second ray 5i in the length, its last ray 3 in the second. 



Caudal moderately forked, the lobes pointed; posterior f of anal 

 long and low, its last third produced in a round lobe. 



Ventrals reaching f distance to origin of anal. If in head. 



Pectoral 1* in head, reaching to base of the ventrals. 



Color silver}", darker above; caudal reddish, 4 or 5 of the center 

 interradial membranes black; a black basal spot. 



85. Cynodon vulpinus Spix. 



One specimen (270), Rio Paraguay at .Asuncion. 



86. Serrasalmo humeralis Cuv. and Val. Pirana. 



Three specimens (78, 193, 204), Rio Paraguay at Asuncion; Arroyo 

 Trementina. 



D. 16; A. 36; lat. 1., 74-78; head 2i; depth 2-2i 



87. Serrasalmo spilopleura Kner. Pirai (pira= fish, tai = tooth). 



Two specimens (74, 203), Rio Paraguay at Asuncion; Arroyo Tre- 

 mentina. 



D. 15; A. 32; lat. 1., SO; head 3-3*; depth If-lf 



88. Metynnis mola sp nov. 



Type No. 10,049, one specimen (part of 191), Arroyo Trementina. 

 Co-types Nos. 10,050-10,051, two specimens (part of 191), Arroyo 

 Trementina; 75 and 85 mm. 

 Head 3f ; depth H; D. 15 or 16; A. 38-40; lat. 1., 72-75. 



