370 Fretp Museum or Narturat History — Zodéxoey, Vor. X. 
Head 4.17 to 4.85; depth 4.85 to 5.75; D. VI-I, 10; A. I, 10; scales 
70 to 86. 
Body elongate, anteriorly subcylindrical, posteriorly compressed; 
head short, quadrate, as wide as deep; snout very short and blunt, 
anterior profile nearly vertical, its length 2.2 to 2.96 in head; eye small, 
lateral, placed high, 4.7 to 5.75; interorbital 3 to 4.3; mouth large, hori- 
zontal, inferior; the upper jaw notably in advance of the lower, the lip 
thickened; maxillary reaching to or past posterior margin of eye, 1.7 to 
2.2 in head; teeth in upper jaw in a single series, very slender, recurved, 
somewhat compressed and grooved at apices, tricuspid in young, with 
nearly smooth cutting edge in adult; lower jaw with 2 series of teeth, 
the outer series nearly horizontal, directed forward, more or less exposed 
in young, but completely hidden in the gums in adult; second series 
composed of comparatively few, rather strong, vertical or slightly re- 
curved, pointed teeth; gill-openings vertical, not extending forward; 
scales small mostly ctenoid, extending forward nearly to interorbital 
region; abdomen completely covered with scales; those on predorsal 
region and abdomen very small and partly embedded; origin of first 
dorsal about midway between posterior margin of eye and origin of 
second dorsal, the spines produced in adult males, sometimes reaching 
past middle of base of second dorsal; origin of second dorsal midway 
between posterior margin of eye and base of caudal or slightly nearer the 
latter, notably higher in adult males than in females; caudal fin scaly at 
base, the margin rounded; anal fin similar to second dorsal, but scarcely 
as high; ventral fins forming almost a perfect circular disc; pectoral 
fins broad at base, rounded, 1.05 to 1.4 in head. 
Color dark green. Young with a dark lateral band, which later 
breaks up into more or less confluent spots; sides also with dark cross- 
bars, which are very indistinct in our largest specimens; back in young 
with dark reticulations; scales usually with roundish spots which are 
largest and most distinct on caudal peduncle. Dorsal fins spotted or 
not; anal fin with a dark stripe near its margin. 
We have 8 specimens of this species, ranging from 55 to 100 mm. in 
length. One of these was taken at Paraiso, on the Pacific slope, in a 
small tributary of the Rio Grande, and the others are from various places 
in the Chagres Basin. We are unable to separate the Pacific slope 
specimen from those of the Rio Chagres. Our specimens were all taken 
in upland streams where the species inhabits the rocky rapids. By 
means of its ventral sucking disc, it is able to cling closely to the rocks 
and is extremely difficult tocapture. It is therefore quite certainly not 
as rare as the small number captures would indicate. 
Habitat: Both slopes of Panama and Western Ecuador. 
