32 MEMOIRS OF THE CARNEGIE MUSEUM.' 



10025, I. U. M., one, 26 mm. to base of caudal. Arroyo Chagalalina, Para- 

 guay basin. J. D. Anisits. Type of rathbuni. 



10030, I. U. M., one, 25 mm. to base of caudal. Arroyo Trementina. J. 

 D. Anisits. Type of stramineus. 



A close comparison of rathbuni and stramineus in the light of the study of the 

 group of the Cheirodontince makes it quite probable that stramineus is the female 

 of rathbuni. 



No additional material was collected by Haseman. 



Head 4; depth 3; D. 11; A. 19 or 20; scales 35, 9 between dorsal and ventrals; 

 eye 2.6-3 in the head, equal to the interorbital ; snout about half length of eye. 



Elongate, compressed; preventral area rounded, without a distinct median 

 series of scales, of which there are eleven between ventrals and the isthmus; pre- 

 dorsal area rounded, with about fourteen scales, of which about nine in front of 

 the dorsal are in a median series; occipital process very short, reaching about 



Fig. 9. Aphyocharax rathbuni Eigenmann. Greatly enlarged. 



one-seventh to the dorsal; frontal fontanel about half as long as the parietal with 

 its groove; second suborbital in contact with the lower limb of the preopercle 

 along its entire margin; a naked wedge behind it; postorbital strong, its margin 

 more convex in the male than in the female, having a naked area around its entire 

 distal margin; lateral line tubes on the postorbital and on the third suborbital 

 strong; mouth very small, the maxillary very short, its margin very convex, not 

 reaching the anterior margin of the eye; premaxillary with about five teeth, maxil- 

 lary with one to three; mandible with six to nine teeth, the first three rapidly 

 graduate. 



Origin of dorsal a Uttle nearer base of caudal than tip of snout; origin of anal 

 under dorsal; anal with a slight lobe, the end of the fin rounded; most of the anal 



