1914. 



NATURAL SCIENCES OF PHILADELPHIA. 



243 



broad. Inner buccal folds broad. Nostrils together, anterior 

 simple pore with hind cutaneous rim exposing larger posterior aper- 

 ture in crescent, and anterior falls about last third in snout length. 

 Interorbital evenly convex. Infraorbital broad, covers cheek, with 

 few radiating striae, and its width f of eye-diameter. Hind pre- 

 opercle edge nearly vertical. Opercle narrow, with a few obsolete 

 striae, and its width trifle less than | its length. 



Gill-opening forward to front eye edge. Gill-rakers about 10 + 13, 

 slender, tapering, pointed, and slightly shorter than gill-filaments, 

 which latter about half of eye. Isthmus narrow, constricted, surface 

 rounded though with median groove in front. Branchiostegals 

 moderate, subequaL 



Fig. 6. — Astyanax rupununi Fowler. (Type. 



Scales disposed in even longitudinal series parallel with 1. 1., 

 mostly uniform in size except those variably smaller along predorsal, 

 breast, .preventral, postventral, caudal base and along anal base. 

 Ventral with free scaly pointed axillary flap about | length of fin. 

 L. 1. complete, decurved slightly below median axis, and extending 

 up a little low along side of caudal peduncle at first. Tubes simple, 

 and better exposed in posterior course of 1. 1. 



Dorsal origin midway between snout tip and caudal base, first 



branched ray longest, extends back well beyond tips of last, and 



depre.ssed fin reaches half way to caudal base. Adipose fin inserted 



little nearer depressed dorsal tip than caudal base, and its length 



17 



