30 PROCEEDINGS OF THE NATIONAL MUSEUM vol. u9 



row and partially on adjoining third and fifth scale rows; expanding 

 over anal fin to include one-half of third scale row and on caudal 

 peduncle extending downward to all but the lowermost vertical scale 

 row. Primary horizontal stripe ending on caudal peduncle in Peru- 

 vian specimens but extending posteriorly onto caudal fin as a very 

 narrow wedge on most specimens from British Guiana. 



Above primary horizontal stripe, pale stripe extending from eye to 

 caudal peduncle. Melanophores scattered over entire surface of this 

 stripe being thicker and heavier in region of fifth through eleventh 

 and sixteenth to twentieth vertical scale rows. These areas consti- 

 tute oblique bands. Secondary horizontal stripe dorsal to silvery 

 lateral stripe, and extending from posterior upper end of gill cover 

 through second row of scales onto caudal peduncle. Secondary hori- 

 zontal stripe darker and wdder at posterior margin of each scale in 

 second row. Back above secondary horizontal stripe dark, rather 

 densely covered with melanophores. Sides below primary horizontal 

 stripe lightcolored with few scattered melanophores. On sixth scale 

 roAV tertiary horizontal stripe extending from below operculum along 

 sides of belly, where extending over or interrupted by pelvic fins, and 

 then continuing to posterior end of base of anal fin. Tertiary hori- 

 zontal stripe narrow and sometimes absent or restricted to region 

 behind pelvic fins. Portion of tertiary horizontal stripe on head 

 along surface of third orbital bone. Pectoral and pelvic fins without 

 dense aggregations of melanophores. Sometimes rather weak aggre- 

 gation of melanophores present along uppermost and lowermost 

 principal caudal fin rays. Dorsal fin dusky on its anterior distal 

 portion and first and second unbranched rays frequently dark. Anal 

 fin of male and sometimes female dusky along its distal and anterior 

 regions. Sometimes this duskiness not evident. 



Color in life. — The color description given below agrees well 

 with that given by Eigenmann (1909, p. 45) for live specimens of 

 Poecilobrycon erythrurus from British Guiana. The specimens used 

 here were collected in British Guiana by Louis Chung in 1955 or 1956 

 but are without definite locality. Midanterior region of dorsal fin with 

 single bright red spot. Red spots on base of upper and lower lobes 

 of caudal fins and bright red spots on anterior base of anal fin and 

 proximal region of pelvic fin. In some specimens these red spots 

 almost absent. Location of these spots well shown in color photograph 

 by Innes (1953, p. 192). Photograph in Axelrod and Schultz (1955, p. 

 248) shows color of this species well. Primary horizontal stripe metal- 

 lic pale green-gold. Caudal fin posterior to metallic pale green-gold 

 stripe with few streaks of white pigment. Thin red line extending 

 lengthwise through center of metallic pale green-gold stripe. Fre- 

 quently this red line broken into series of streaks, reduced in length or 



