368 MEMOIRS OF THE CARNEGIE MUSEUM 



Origin of the dorsal a little in advance of the middle, pointed, the rays very 

 rapidly decreasing from the highest, which is equal to about a third of the length. 



Anal emarginate, its origin and the third dorsal ray about equidistant from the 

 snout; ventrals extending slightly beyond origin of anal; pectorals beyond base of 

 ventrals. 



Straw-colored, with a silvery lateral band, slightly iridescent. A large, 

 conspicuous, subcircular spot over the sixth to eighth scale of the lateral line, 

 occupying the width of two scales (this spot frequently with a lunate encroach- 

 ment in front) ; upper part of opercle and area below eye spotted, sometimes the 

 rest of the cheek also spotted; a black median line more or less evident; a large 

 caudal spot extending to near the middle (sometimes farther) of the median caudal 

 rays; scales of the back always broadly margined with black, those of the flanks 

 less so ; above the anal the markings of the margin of the scales mixed with the lines 

 of chromatophores following the muscle segments; tips of caudal nigrescent; anal 

 nearly uniformly dotted, or the base and tip dotted, the rest hyaline; first anal rays 

 milk-white. 



224. Phenacogaster microstictus Eigenmann. (Plate LIII, fig. 4.) 



Phenacogaster microstictus Eigenmann, Ann. Carnegie Mus., VI, 1909, 30; Repts. 



Princeton Univ. Exp. Patagonia, III, 1910, 431. 



Type, 48 mm. Tumatumari, Lower Potaro. (Carnegie Museum Catalog 

 of Fishes No. 1063.) 



Cotypes, seven specimens, 28 mm. Konawaruk. (C. M. Cat. No. 1064a-c; 

 I. U. Cat, No. 11751.) 



Cotype, one specimen, 29 mm. Rockstone. (C. M. Cat. No. 1065.) 



Cotypes, four specimens, about 35 to about 46 mm. Crab Falls. (C. M. 

 Cat. No. 1066; I. IT. Cat, No. 11752.) 



Head 4; depth 2.8; D. 11; A. 37-40, generally 39; scales 6-38 or 39-5; eye 2.5; 

 interorbital 3.5. 



Only one or two small scales in the angles of the overlapping scales of the 

 ventral surface; interorbital slightly convex. Maxillary teeth about seventeen, 

 scattered along most of its length; premaxillary with four tricuspid and five conical 

 teeth in the inner series; two or three teeth similar to the larger ones, and possibly 

 sometimes a few conical teeth in the outer series; mandible with seven larger and 

 a number of minute teeth. 



Scales with concentric striae, but with very tew, or inconspicuous, radial striae. 



Straw-colored; a very faint and small humeral spot over the seventh scale 



