Dec. 28, 1916. FisHes or PANAMA— MEEK AND HILDEBRAND. 341 
Head 2.46 to 3.13; depth 2.35 to 2.95; D. XVI, 9 or 10; A. III, 7 or 8; 
scales 29 to 31. 
Body rather deep, compressed; the back elevated; anterior profile 
distinctly convex in young, straight in adults not possessing a nuchal 
hump, concave in specimens with nuchal hump; head deep; snout long 
and pointed in adult, much shorter and more blunt in young, equal to 
half length of head in specimens about 125 mm. in length, much greater 
than half length of head in large specimens and much shorter than half 
head in very young, 1.6 to 4 in head in specimens ranging from 30 to 263 
mm. in length; eye circular, placed high, lower margin of pupil about on 
level with upper angle of gill-opening, 2.95 to 5.85 in head; preorbital 
broad, about 2 times diameter of eye in large examples, equal to or a 
little less than diameter of eye in very young; mouth moderate, hori- 
zontal; maxillary failing to reach anterior margin of eye, 2.6 to 3.65 in 
head; jaws equal or the upper slightly projecting; the lips thickened, 
the lower with a fleshy lobe on each side; teeth conical, in bands in each 
jaw; gill-membranes broadly connected across isthmus; gill-rakers short, 
about 13 on lower limb of first arch; lateral line interrupted under soft 
portion of dorsal, reappearing on the third row of scales below its 
original course; scales of moderate size, feebly ctenoid, from 2 to 34% 
rows between lateral line and middle of base of dorsal; dorsal fin long, 
its origin over posterior margin of opercle, the spines rather short and 
strong, the last one 2.7 to 3.3 in head, the soft portion varying greatly 
in length among different individuals, usually reaching base of caudal, a 
few of the rays occasionally produced and reaching far beyond this 
point; caudal fin scaly at base, its margin concave; anal fin short, the 
spines strong, the soft portion similar to that of dorsal; ventral fins 
inserted slightly behind base of pectorals, reaching to or past vent; 
pectoral fins moderate, 1.2 to 1.5 in head. 
Color in life greenish brown above, yellowish below. Sides in young 
with well defined black cross-bars, these less distinct in adult; very young 
also with a black lateral band. Lips and gill-membranes blue in adult. 
Dorsal, caudal, anal and ventrals reddish yellow in adult, more greenish 
in young; pectorals greenish. 
This fish is represented by numerous specimens, ranging from 30 to 
263 mm. in length. It is common in the streams on both slopes of 
Panama. 
There is considerable variation with respect to the development of 
the soft portion of the dorsal and anal fins and the number of rows of 
scales between the lateral line and base of dorsal, but our large series is 
ample to show that these are only individual variations. 
Habitat: Isthmus of Panama. 
