248 Annals of the Carnegie Museum. 



5797 (^~b- C. M. 66-132 mm. Santarem, Dec. li, 1909. Haseman. 



5798 a-c. C. M. 105-125 mm. Para, Jan. 17, 1910. Haseman. 

 Head 3.7-3.9; depth 1.5-1.6; D. 17; A. 32-34; serra^ 30-33; inter- 

 orbital 2.33-2.25; cheeks with a naked area equal in width to the 

 suborbital; head 1.5 in the length of the base of the anal; palate with 

 one or two teeth. 



This species, greatly resembling gymnogenys — aureus, is readily 

 distinguished by its black caudal border. The specimens from Par& 

 differ from P. calmoni, for the most part as described by Stein- 

 dachner, in only insignificant details; but the eyes in the specimens are 

 certainly longer than the snout, the end of the upper jaw does not 

 reach below the middle of the eye, and the origin of the ventrals is a 

 little nearer the tip of the snout than the end of the anal. In the 

 types of bilineatus, on the contrary, it is a little nearer the end of the 

 anal. 



14. Pristobrycon striolatus (Steindachner). 



Serrasalmo (Pygocenlyiis) striolatus Steindachner, Anz. K. Acad. Wiss. Wien» 

 1908, p. 360. 



Known only from the types, 180-200 mm. long, coming from tribu- 

 taries of the Rio Para. 



\T. Genus Serrasalmo Lacepede. 

 Serrasalmo Lacepede, Hist. Nat. Poiss., VoL V, 1804, p. 283. 



Type, Salmo rhomheus Linnaeus. 



Body deep, compressed; a series of serrae from below the pectorals 

 to the anus. Teeth in the premaxillary in a single series, trenchant; 

 usually a series of teeth on the palate, but in this respect grading 

 through the heavier jawed, short-nosed species, like maciilatus, into 

 Rooseveltiella; second suborbital covering all or most of the cheek; 

 tongue narrow, free, anal partly scaled; predorsal line naked. 



Distribution. — Orinoco, and Guianas south to the Rio San Frantisco 

 and the La Plata basin. Not occurring in the Magdalena, on the 

 Pacific slope, nor in the short rivers draining into the Atlantic between 

 the Itapicuru and the Uruguay. 



Key to the Species of Serrasalmo. 

 a. Depth more than 2 in the length to the end of the lateral line. See also 5. 

 humeralis gracilior. 



b. Interorbital 2.5-2.7 in the head; snout, which is acutely pointed, longer 

 than the eye; chin sharply pointed, entering the profile; lower jaw 2 in 



