EIGENMANN: the freshwater fishes of BRITISH GUIANA . 405 



conical teeth to its tip; a strong canine at each end of the premaxillary, and two 

 series of conical teeth between them; four graduated canines on the lower jaw in 

 front, the last being much the largest, these followed on the sides by a series of 

 about thirty graduated conical teeth; predorsal area naked. 



259. Acanthocharax microlepis sp. nov. (Plate LXI, fig. 1.) 



Type, 105 mm. Tumatumari. (Carnegie Museum Catalog of Fishes No. 

 2138.) 



Cotypes, forty-three specimens, 55-103 mm. Tumatumari. (C. M. Cat. 

 No. 2139a-j; I. U. Cat. No. 12315.) 



Cotypes, three specimens, 48-85 mm. Crab Falls. (C. M. Cat. No. 2140- 

 a-b; I. U. Cat. No. 12316.) 



Cotypes, twenty-two specimens, 51-82 mm. Rockstone. (C. jSI. Cat. No. 

 2141a-('; I. U. Cat. No. 12317.) 



Head 3.4-3.66; depth 2.7-2.8; D. 11; A. 30-34; scales 9-47 to 53-6; eye .75 

 in snout, 2.75 in head, .66 in interorbital. 



Compressed, head and shoulders heavy, profile depressed over the eye, arched 

 from base of the occipital process to the dorsal; preventral area rounded; a deep 

 notch in the clavicle for the reception of the pectoral, the process below the pectoral 

 broad-tipped behind, no free spine in front; postventral area trenchant, a wide 

 naked area below the second suborbital; mouth oblique, the maxillary extending 

 beyond the first suborbital; distance from tip of snout to end of maxillary equal 

 to distance from tip of snout to posterior margin of the eye; gill-rakers 5 + 9, 

 the longest .4 of the eye. 



Scales very regularly imbricate, except on the breast, without longitudinal 

 striae. A naked area beginning at the dorsal, widening forward and extending on 

 either side of the occipital process; fins naked; lateral line decurved, complete. 



Origin of the dorsal nearer the snout than to the tail ; origin of anal and middle 

 of dorsal nearly equidistant from the snout; anal distinctly emarginate; ventrals 

 reaching anal, pectorals to near middle of ventrals. 



A humeral spot over the fourth to sixth scale of the lateral line; a large, diffuse 

 caudal spot. 



Heterocharax gen. nov. 



Type, Heterocharax macrolepis sp. nov. 



Lateral line complete; origin of anal under the dorsal; scales moderate, 

 cycloid; a spine on the lower angle of the preopercle; maxillary without a canine, 

 the teeth graduated in both directions from the fifth; premaxillary with a single 



