30 Annals of the Carnegie Museum. 



All the markings except the humeral spot may be very faint. 

 Dorsal, caudal, and anal red in life. 

 Vertebrae 12 -f 19- 



Phenacogaster microstictus sp. nov. 



Type, 48 mm. (No. 1063 Carnegie Museum Catalog of Fishes.) 

 Tumatumari, Lower Potaro. 



Cotypes, 7 specimens, 28 mm. Konawaruk, Essequibo River. 

 (C. M. Cat. No. 1064, a-c\ I. U. Cat. No. 11751.) 



Cotype, i specimen, 29 mm. Rockstone, Essequibo River. (C. 

 M. Cat. No. 1065.) 



Cotypes, 4 specimens, about 35 to about 46 mm. Crab Falls, Esse- 

 quibo River. (C. M. Cat. No. 1066; I. U. Cat. No. 11752.) 



Head 4 ; depth 2.8 ; D. 11 ; A. 37-40, most often 39 ; scales 6-38 

 or 39-5 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 with 

 about seventeen teeth 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, very few, or inconspicuous, radial striae. 



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

 scale of the lateral line ; a dark deep-lying line ; two small deep-lying 

 black spots at the bases of the caudal lobes ; no caudal spot ; caudal, 

 except the middle of the base of the lobes, dusky ; base and margin of 

 anal dotted, the middle hyaline ; sides of head and body profusely 

 dotted, the dots on the flanks and back margining the scales, the 

 margin consisting of a single row of chromatophores on the flank, of 

 several rows on the back ; dots over the anal muscles following the 

 intermuscular septa. Cotypes all very much lighter. 



In one of the Crab Fall specimens the humeral spot is conspicuous 

 owing to the expansion of the chromatophores. 



Genus Creagrutus Giinther. 



Creagrutus melanzonus sp. nov. 



Type, 44 mm. (No. 1067 Carnegie Museum Catalog of Fishes.) 

 Crab Falls. 



