Dec. 28,1916. FisHes of PANAMA— MEEK AND HILDEBRAND. 283 
KEY TO THE SPECIES. 
a. Scales regularly placed, in 35 to 41 oblique series from upper 
angle of gill-opening to base of caudal; 11 to 13 scales in advance 
of dorsal; 10 or 11 between dorsal and adipose; 7 complete, 
longitudinal rows between lateral line and base of dorsal. Color 
silvery, with a plumbeous lateral band. Breeding males with- 
out tubercles on head and margin of scales; fins nearly smooth. 
emperador, p. 283. 
aa. Scales more or less irregularly placed, in 40 to 48 oblique series 
from upper angle of gill-opening to base of caudal; 12 to 15 
scales in advance of dorsal; 12 to 14 between dorsal and adipose; 
8 complete longitudinal rows between lateral line and base of 
dorsal. Color dark silvery, lateral band very dark posteriorly. 
Breeding males with small tubercles on head and margin of 
scales; the fins with barbs, very rough to the touch. 
cascajalensis sp. nov., p. 284. 
31. Bryconamericus emperador (Eigenmann & Ogle). 
Astyanax emperador Eigenmann & Ogle, Proc. U.S. Nat. Mus., XX XIII, 
1907, 26 (Empire, Panama Canal Zone). 
Bryconamericus emperador Eigenmann, Indiana Univ. Studies, No. 18, 
Pt. II, 1913, 11. 
Head 3.05 to 4; depth 2.5 to 3; D. roor 11; A. 24 to 29; scales 35 to 41. 
Body rather deep, compressed, the back elevated; head small; 
snout conical, 3.8 to 4.8 in head; eye 2.5 to 2.85; interorbital 2.75 to 3; 
mouth small; jaws subequal; maxillary reaching anterior margin of 
pupil, slightly longer than snout; premaxillary teeth in 2 series, the 
outer series irregular, with ro teeth, the inner series regular with 8 to 
1o teeth; maxillary with 2 small teeth near its juncture with the pre- 
maxillary; lower jaw with 8 large teeth anteriorly and abruptly smaller 
ones at sides; gill-rakers short, about 12 on lower limb of first arch; 
lateral line complete, moderately decurved; scales moderate, striate, 
tr to 13 in advance of dorsal, 10 or rr between dorsal and adipose, 7 
or 8 longitudinal rows between anterior dorsal rays and lateral line; 
dorsal fin inserted midway between tip of snout and base of caudal; 
adipose fin about one-third as far from base of upper caudal ray as 
from base of last dorsal ray; caudal fin forked, the lower lobe the longer; 
anal fin rather long, its origin a little behind base of last dorsal ray, about 
midway between base of pectorals and base of caudal; ventral fins reach- 
ing to or slightly past vent, inserted midway between tip of snout 
and base of last anal ray; pectoral fins usually reaching to base of ven- 
trals, inserted midway between tip of lower jaw and base of ventrals. 
