Dec. 28, 1916. Fisnes or PANAMA— MEEK AND HILDEBRAND. 249 
7. Genus Chzetostomus Tschudi. 
Chetostomus Tschudi, Fauna Peruana, Pisc., XV, 1840, 489 (type 
Chetostomus loborhynchus Tschudi). 
Body elongate, anteriorly depressed, wider than deep, ventral surface 
flat; head low, broad; snout obtuse, with a naked margin and without 
spines or tentacles; plates on head rather smooth, without ridges or 
carinations; back and sides covered with spinulate but not carinate 
scutes; lower surface of head and abdomen naked; mandibular ramus 
nearly equal to interorbital width. Adipose fin present. This genus is 
represented by a single species in Panama. 
7. Chzetostomus fischeri Steindachner. 
Chetostomus fischeri Steindachner, Denkschr. K. Ak. Wiss. Wien, 
XLI, 1879, 162, Pl. IV (Rio Mamoni, near Chepo); Jordan & 
Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 16; Regan, 
Trans. Zool. Soc. London, XVII, Pt. III, 1904, 248. 
Head 3 to 3.25; depth 5.15 to 6; D. 1, 8; A. I, 5; lateral scutes 24 or 25. 
Body anteriorly depressed; caudal peduncle posteriorly compressed; 
dorsal profile convex; ventral surface straight and flat; head low and 
wide, its upper surface spinulate, but without ridges or carinations; 
snout obtuse, its margin without granules, spines or tentacles, 1.5 to 
1.65 in head; eye 6.7 to 9.3; interorbital 2.95 to 3.6; mouth wholly 
inferior, broad; the lips expanded, papilose, forming a sucking disc, 
the lower lip with small lobes along its posterior margin and a small 
barbel on its lateral margin near angle of mouth; teeth situated on the 
ramii of the jaws, small, numerous, slender, bifid and curved inward 
near the tips, the ramus of lower jaw 1 to 1.3 in interorbital; interopercle 
with 1 or 2 short spines; back and sides completely covered with spinu- 
late but not carinate scutes, 6 scutes between dorsal and adipose, 10 or 
11 from anal to base of caudal; lower surface of head and abdomen com- 
pletely naked; dorsal fin inserted a little in advance of base of ventrals, 
somewhat nearer tip of snout than adipose fin, its base equal to distance 
from the base of its last ray to tip of adipose, its spine 1.15 to 1.45 in 
head; adipose fin well developed, inserted slightly nearer base of upper 
ray of caudal than base of last ray of dorsal; caudal fin emarginate, the 
lower rays the longest; anal fin small, its origin a little behind last ray 
of dorsal; ventral fins reaching past origin of anal; pectoral fin large, 
reaching beyond middle of ventrals; the spines of all the fins with 
spinules. 
Color uniform black above; abdomen white. Tips of dorsal and 
caudal reddish in life. 
