Durbin : The Expedition to British Guiana. 65 



Maxillary with two or three six- to seven-pointed chisel-shaped teeth. 

 Dentary with four broad seven-pointed teeth followed by three or four 

 minute teeth on the sides. 



Gillrakers about 6 -f- 9. 



Scales cycloid, regularly imbricate, no interpolated scales or rows 

 of scales ; striae few, variable in number. Caudal scaled half way 

 to the end of the longest rays. Anal sheath of three or four normal 

 scales, which extend over the bases of the first seven or eight rays. 

 Axillary scale present. Pores developed on seven or eight scales ; 

 lateral line slightly decurved. 



Origin of the dorsal about equidistant from the snout and caudal, 

 the penultimate ray 0.4 of the longest, which is 3J in the length. 

 Origin of the anal on the vertical from the second scale behind the 

 dorsal ; anal emarginate, longest ray equal to the base ; caudal half the 

 length of the eye longer than the head. Ventrals on the vertical from 

 the first dorsal ray ; ventrals just reaching the anal. Pectorals not 

 reaching the ventrals. 



Humeral spot distinct, but not heavy, not conspicuously elongated. 

 Lateral stripe the width of one scale, not so intense as the humeral 

 spot, expanded on the caudal peduncle, but not continued upon the 

 fin ; scales overlying the lateral stripe distinctly silvery. No caudal 

 spot. First five anal rays, the caudal, and all of the dorsal dusky. 

 Each median dorsal scale with a roundish dark spot. Scales of the 

 upper half of the sides outlined with dusky. A few chromatophores 

 scattered about the base of the anal and aggregated so as to form a 

 small dark spot or line on the ventral side of the caudal peduncle. 

 Top of the head dark. The lateral stripe probably red in life. 



Genus Hyphessobrycon Durbin. 

 Hyphessobrycon minor sp. nov. 



Type, 19 mm. (No. 1189 Carnegie Museum Catalog of Fishes.) 

 Konawaruk. 



Cotypes, 2 specimens, 21-25 mm - Konawaruk. (I. U. Cat. No. 

 11767-) 



Distinguished by intense submarginal black dorsal spot on the first 

 six or seven rays. Tips of first dorsal rays and an area just below the 

 black spot white. Humeral spot black, small, vertically elongate. 

 Teeth in inner row of premaxillary and maxillary not narrowly tricus- 

 pid nor conical. Small slender fishes with small mouth. 



