244 PROCEEDINGS OF THE ACADEMY OF [Apr., 



about I of eye. Anal with long base, inserted below last branched 

 dorsal ray base, first branched ray longest equals half length of base, 

 and lower edge nearly straight. Caudal well forked, pointed lobes 

 about equal. Pectoral low, pointed, reaches slightly beyond ventral 

 origin, though not back till opposite dorsal origin. Ventral inserted 

 midway between pectoral and anal origins, reaches back f to anal. 

 Vent at tip of depressed ventral. 



Color in alcohol largely dull brownish on back and upper surface 

 of head. Sides of head and trunk paler than back, and becoming 

 still more so, or whitish, on ventral region. All scales of back and 

 sides with darker brownish edges, made up of dark dots. Sides of 

 head, opercle, postorbital and muzzle sprinkled with larger dusky 

 dots. Iris slaty. Slightly above level of eye centre, just above 

 1. 1., and about opposite middle in length of pectoral, a blackish 

 ellipsoid blotch, its length about equal to eye. From its upper front 

 end and its entire hind end a pale area extends transversely as two 

 ill-defined pale or whitish spots, posterior much greater in extent. 

 Extending back along vertebral axis a dusky line begins behind pale 

 area and continues back along caudal peduncle side, where it widens, 

 to expand still more at caudal base into large dusky or blackish 

 blotch, and also refiected out on median caudal rays to their tips. 

 Fins all whitish, dorsals and caudal tinged grayish. Distal edge of 

 anal its whole extent slightly tinged grayish. 



Length 64 mm. 



Type, No. 39,228, A. N. S. P. Rupununi River, British Guiana. 

 1912. J. Ogilvie. 



No. 39,329, paratype, same data. Head 3f; depth 2i}; D. iii, 

 9; A. IV, 28, i; scales 36 in 1. 1. to caudal base and 3 ? more on latter; 

 7 scales above 1. 1.; 7 scales below 1. 1. to ventral origin; 8 scales 

 below 1. 1. to anal origin; 14 predorsal scales; snout 4 in head; eye 

 3; maxillary 2|; interorbital 2f; length 62 mm. 



This species appears to be related to Astyanax wappi (Valen- 

 ciennes), as described from the type by Eigemnann.^^ It differs 

 in the smaller head, deeper body, and larger eye. There are, how- 

 ever, no ''traces of longitudinal streaks between the rows of scales." 



(Nametl for the Rupununi River.) 

 Moenkhausia chrysargyrea leucopomis subsp. nov. Fig. 7. 



Head 3|; depth IfV; D. iii, 9; A. iv, 26, i; P. i, 13; V. i, 7; 

 scales 34 in lateral line to caudal base and 2 ? more on latter (squama- 



•' Mem. Carnegie Muh., V. 1912, p. 3"i5, PI. .")2, fig. 1. 



