44 



PROCEEDINGS OF THE NATIONAL MUSEUM 



and Venezuela shorter than about 24 mm. in standard length with 

 anal fins much like those of males from British Guiana, Possibly 

 anal fin develops its pointed posterior border only in males longer than 

 about 29 mm. in standard length. 



Radial grooves of scales in that part of third horizontal scale series 

 below dorsal fin rather variable but frequently resemble scales in 

 figure 11. Posterior field mth 1 to 3 (most frequently 2) radial 

 grooves, dorsal and ventral fields with 1 and anterior embedded field 

 with 2 to 6 radial grooves. Scales in a lateral series 28 to 30 (usually 

 29) and 2 to 5 (usually 4) scales in lateral line. Scales in a median 

 series before the dorsal fin 11. Total number of vertebrae 33 to 34 

 with 21 precaudal and 12 to 13 caudal vertebrae. British Guiana 



Figure U.—Poecilobrycon unifasciatus, male, SL 33.4 mm., CAS(IUM) 11703 (see di 

 cussion for remarks on insert drawings of anal and caudal fins). 



specimens all \\dth 34 vertebrae and all specimens recorded below from 

 Igarap^ do Mai Joana, near Manaos, wdth 33 vertebrae. Of specimens 

 examined from Teffe, both with 33 vertebrae. 



Color in alcohol. — (Specimens from British Guiana) Dorsum of 

 head light brown. Primary horizontal stripe beginning on snout and 

 lower jaw, extending posteriorly over maxillary and first orbital bone 

 onto eye. Posteriorly from iris this stripe continuing across part of 

 fourth and fifth orbitals to across opercular bone, not present on 

 fleshy opercular flap and extending tlu"ough foiu-th scale row to end 

 of caudal peduncle as shown in figure 11. On caudal peduncle primary 

 horizontal stripe expanding ventrally to include entire ventral area. 

 On caudal fin primary horizontal stripe covering entire lower lobe 

 except for crescent near lower posterior margin and central clear area 



