eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 373 



Catalogue, V, 1864, 333 (Essequibo; -River Cupai; British Guiana). — Cope, 

 Proc. Acad. Nat. Sci. Phila., 1871, 262 (Ambyiacu). — Eigenmann and Eigen- 

 mann, Proc. U. S. Nat. Mus., XIV, 1891, 55. — Eigenmann, Repts. Princeton 

 Univ. Exp. Patagonia, III, 1910, 439. 

 Brycon macrolepidotus Muller and Troschel, Horse Ichth., I, 1845, 15; in Schom- 



burgk, Reisen, III, 1848, 635 (Essequibo; Mazaruni). 

 Chalceus ararapeera Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 

 244 (Essequibo). 



Five specimens, 93-214 mm. Konawaruk. (C. M. Cat. No. 1961a-c; 

 I. U. Cat. No. 12202.) 



Five specimens, 95-110 mm. Gluck Island. (C. M. Cat. No. 1962a-c; 

 I. U. Cat. No. 12203.) 



Twenty-six specimens, 93-244 mm. Tumatumari. (C. M. Cat. No. 1963a-/; 

 I. U. Cat. No. 12204.) 



Head 3.5-4; depth 3.6; D. 12; A. 11; scales 3.25-37 or 38-2, twenty to twenty- 

 two scales in the series just above the lateral line. Eye 1.3 in snout, 3.6 in head, 2 

 in interorbital; 1, 3, 1.3 respectively in the young. 



Elongate, ventral profile with a greater arch than the dorsal; ventral surface 

 rounded, with a regular median series of scales; dorsal surface very broad, with a 

 median series of seven scales before the dorsal ; profile from the dorsal to the snout 

 slightly curved, little descending; head broad, smooth, and flat above, the fontanels 

 linear, becoming obliterated with age; occipital process very short, scarcely evident 

 externally. 



Cheeks with a narrow naked margin behind in the adult; the second suborbital 

 in contact with the lower limb of the preopercle, but leaving a naked margin in the 

 adult; premaxillaries meeting at an angle, with a considerable horizontal extent, 

 meeting the straight-margined premaxillaries at an angle. Mouth terminal, the 

 upper jaw projecting; the teeth much as in Brycon, lower jaw with two series of 

 teeth; those of the outer series graduated, multicuspid, with ribbed convex outer sur- 

 and concave inner surface, fourteen on each side; inner series consisting of minute 

 face conical teeth, much more numerous than those of the outer series, the median pair 

 much enlarged; each premaxillary with an outer series of about ten tricuspid 

 slightly graduated teeth; an inner series of about six multicuspid teeth, of which 

 the second is the largest, those following rapidly graduated; a middle series of 

 two teeth, one outward from the space between the first and second of the inner 

 series and one outward from the space between the second and third; maxillary 

 with a series of teeth for nearly its entire length, those near its angle tricuspid, 



