486 MEMOIRS OF THE CARNEGIE MUSEUM 



Acara unicolor Heckel, Ann. Wiener Mus., II, 1840, 357 (Barra do Rio Negro). 

 Acaropsis rostratus Schomburgk, Fishes Brit. Guiana, II, 1843, 163, pi. 15 (Rio 



Negro) . 



One specimen, 68 mm. Twoca Pan. (C. M. Cat. No. 2283.) 



One specimen, 80 mm. Rupununi. (C. M. Cat. No. 2297.) 



One specimen, 79 mm. Cane Grove Corner. (C. M. Cat. No. 2284.) 



One specimen, 72 mm. Gluck Island. (C. M. Cat. No. 2285.) 



Six specimens, 39-63 mm. Wismar. (C. M. Cat. No. 2286a-c; I. U. Cat. 

 No. 12459.) 



Thirteen specimens, 46-188 mm. Maduni Creek. (C. M. Cat. No. 2287a-d; 

 I. U. Cat. No. 12458.) 



Six specimens, 65-94 mm. Rockstone. (C. M. Cat. No. 2288a-c; I. U. Cat. 

 No. 12457.) 



Thirty-eight specimens, 60-202 mm. Lama Stop-Off. (C. M. Cat. No. 

 2289a-/;; I. U. Cat. No. 12456a-e.) 



Head 2.4-2.75; depth 1.9-2.2; D. XII-XIV,9-11; A. 111,7-9; scales 22-24 

 along the middle line, half a scale between the lateral line and the soft dorsal. 

 Lateral line 14-16 + 6-10; eye 3-3.5 in head, .8-1.2 in interorbital. 



Snout pointed; mouth oblique, lower jaw projecting, maxillary reaching to 

 below the eye; premaxillary-maxillary border 2 in the head; an outer row of conical 

 teeth, a compact band of villiform teeth within it; prcorbital 3 to 4 in the diameter 

 of the eye. Eleven short gill-rakers on the lower arch. 



Two or three rows of scales on the cheek; dorsal and anal entirely naked, no 

 dorsal sheath. 



Pectorals extending to above the middle of the anal; caudal rounded; dorsal 

 spines graduated, soft dorsal and anal prolonged to near the end of the caudal; 

 ventral filament rarely reaching caudal peduncle, one-half to three-fifths as long 

 as deep. 



Scales of lower part of sides with silvery spots; a dark band down and back 

 from the eye to the angle of the preopercle, becoming divided with age into two 

 spots, of which the lower is ocellated; a dark band from the eye to the end of the 

 soft dorsal, intensified into a spot in the middle, but only the spot evident in 

 the old; a small spot above the origin of the lateral line, another at the base of 

 the upper caudal rays; vertical fins with light or dark spots; in the old the soft 

 dorsal and anal become dark, there being conspicuous hyaline spots on the last 

 few membranes; caudal rays dusky, the membranes alternately black and hyaline. 

 Old individuals sometimes irregularly blotched with black. 



