DEC. 28, 1916. FISHES OF PANAMA MEEK AND HILDEBRAND. 297 



is somewhat darker and the blackish bars on sides are usually more 

 distinct. 



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., Zool. 



Ser., X, 1913, 184 (Upper Chagres, Panama). 



Head 3.3 to 4.1; depth 3.15 to 3.9; D. n, 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 



