354 MEMOIRS OF THE CARNEGIE MUSEUM 



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 

 backward 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. 



214. Astyanax mucronatus Eigenmann. (Plate LI, fig. 4.) 

 Astyanax mucronatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 19; Repts. 



Princeton Univ. Exp. Patagonia, III, 1910, 433. 



Type, 53 mm. Tumatumari, above the falls. (Carnegie Museum Catalog of 

 Fishes No. 1025.) 



Cotypes, three specimens, 51-54 mm. Tumatumari, above the falls. (C. M. 

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



Cotypes, fourteen specimens, 46-73 mm. Sand-bank in Potaro at Tukeit. 

 (C. M. Cat. No. 1027a-e; I. U. Cat. No. 11726.) 



Head 3-6; depth 2.3-2.6; D. 11; A. 25-26, rarely 27; scales 6-34 or 35-5 

 ( rarely 4) . Eye 2.7 in the head, 2 in the head without the opercle ; interorbital 3-3.5 

 in the head. 



Compressed, subrhomboidal, with heavy head and slender caudal peduncle. 

 Dorsal profile slightly depressed over the eye, rising with a gentle curve to the 

 origin of the dorsal, abruptly descending to the end of the dorsal and then with a 

 more gentle slope to the caudal peduncle. Ventral profile more regularly arched. 

 Preventral region broadly rounded; postventral area more narrowly rounded; 

 predorsal area keeled, with a median series of eight scales. 



Occipital crest exceptionally narrow at the base; about one-fourth of the 

 distance from its base to the dorsal, bordered by three scales on the sides; skull 

 narrow, slightly convex, smooth. Fontanels very narrow and long, the frontal 

 fontanel as long as the parietal. Second suborbital leaving but a very narrow naked 

 area. Maxillary but little longer than snout, 3.3 in the head. Premaxillary with 

 two or three teeth in the front series, five teeth in the second series, their denticles 

 in a straight line; two teeth on the maxillary; lower jaw with eight teeth arranged 

 in a crescent (four on each side), and smaller teeth on the sides. 



Gill-rakers 5 + 10. 



Scales very regularly imbricate, without interpolated or omitted rows. Each 

 scale with several slightly diverging stria? ; anal sheath of a single row of scales 

 along the base of the anterior rays; caudal naked. 



