Dec. 28, 1916. FisHes of PANAMA— MEEK AND HILDEBRAND. 207 
is somewhat darker and the blackish bars on sides are usually more 
An examination of specimens from Guatemala shows these to repre- 
sent a distinct species and should be known as Brycon guatemalensis 
Regan. The teeth are like those of B. striatulus, but the scales are 
larger (53 or 54 in a lateral series). 
Habitat: Atlantic slope of Panama. 
42. Brycon petrosus Meek & Hildebrand. 
Brycon petrosus Meek & Hildebrand, Field Mus. Nat. Hist. Pub., Zodl. 
Ser., X, 1913, 184 (Upper Chagres, Panama). 
Head 3.3 to 4.1; depth 3.15 to 3.9; D. 11, rarely 10; A. 24 to 30; 
scales in lateral series 53 to 58. 
Body elongate, compressed, profile straight over eyes, somewhat 
elevated at nape; head moderate; snout pointed, 3.44 to 4 in head; eye 
2.83 to 4.23; interorbital 2.15 to 4; mouth moderate; upper jaw strongly 
projecting; maxillary reaching slightly past anterior margin of pupil, 
2.1 to 2.66 in head; premaxillary teeth laterally in only 2 series, the 
second series exposed at least anteriorly, not covered by lower lip; the 
last or transverse series rather close in front of teeth in lower jaw; the 
outer series of premaxillary teeth usually 14, rarely 16, in number; 
outer series in lower jaw with 8 strong teeth of about equal size and 2 
or 3 smaller ones behind laterally; gill-rakers about 12 to 14 on lower 
limb of first arch; lateral line decurved, notably below median line of 
side; scales moderate, regularly placed, 16 to 18 vertical rows crossing 
back between dorsal and adipose; 3 complete rows between lateral line 
and base of pectoral; dorsal fin inserted a little nearer base of caudal 
than tip of snout; adipose fin half 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 short, its base slightly longer than head, its 
origin a little behind base of last dorsal ray, slightly nearer base of 
caudal than base of pectoral; ventral fins usually reaching vent, inserted 
nearer origin of anal than base of pectoral; pectoral fins inserted under 
margin of opercle, usually failing to reach base of ventrals by 2 to 4 
rows of scales. 
Color silvery, bluish above, lighter below; sides plain silvery; an 
obscure shoulder spot present in the smaller specimens, wanting in all 
of our larger individuals; very young with a dark lateral band. A 
large black caudal spot present at all ages. 
This species is represented by numerous specimens, ranging from 50 
to 285 mm. in length. It is less abundant than B. chagrensis and does 
not grow as large. It was not found in the lowland waters but it is 
A 
