ElGENMANN : THE EXPEDITION TO BRITISH GUIANA. 19 



Compressed, dorsal and ventral profiles equally curved ; snout 

 narrow, pointed, profile not depressed over the eye ; preventral area 

 rounded, without a distinct median series of scales ; postventral area 

 narrowly rounded ; predorsal area keeled, with a median series of nine 

 or ten scales. 



Occipital process very narrow, about -i as long as the distance of its 

 base from the dorsal, bordered on each side by three scales ; inter- 

 orbital convex, frontal fontanel much shorter than the parietal ; second 

 suborbital narrow, leaving a naked area, which is more than half as 

 wide as the bone itself; maxillary equals snout in length, its front 

 margin very convex ; width of lower jaw about half the orbit ; pre- 

 maxillary with two to four teeth in the front series, five five-pointed 

 teeth in the second series ; maxillary with three teeth, of which one is 

 minute ; dentary with five or six five-pointed teeth, graduate ; ab- 

 ruptly a series of minute conical teeth on the sides. 



Gill rakers n + 18. 



Scales regularly imbricate, no interpolated or omitted series ; anal 

 sheath of a single series of scales along anterior part of anal ; lateral 

 line little decurved, sometimes broken or interrupted on the tail ; each 

 scale with several radiating striae. 



Origin of dorsal midway between tip of snout and base of middle 

 caudal rays ; highest dorsal ray nearly 4 in the length ; origin of anal 

 and ninth to eleventh dorsal ray equidistant from, snout ; anal very 

 slightly emarginate ; ventrals considerably in front of the vertical from 

 the first dorsal ray, just reaching anal ; pectorals just to ventrals or a 

 trifle shorter. 



Dusky ; a definitely circumscribed oval caudal spot, not continued 

 forward or backwards on the middle caudal rays ; a well-defined bar 

 crossing the second and third scales of the lateral line ; sides of head 

 and body everywhere profusely dotted; dorsal, caudal, and anal 

 dotted; base of caudal with the outlines of the rays and their cross- 

 breaks outlined in black, making this part of the fin darker. 



Astyanax mucronatus sp. no v. 



Type, 53 mm. (No. 1025 Carnegie Museum Catalog of Fishes.) 

 Tumatumari, above fall. 



Cotypes, 3 specimens, 51-54 mm. Tumatumari, above fall. (C. 

 M. Cat. No. 1026; I. U. Cat. No. 11725.) 



