310 Fretp Museum or Natura History — Zod oey, Vor. X. 
Body elongate, compressed; size small; head short; snout blunt; 
frontal and parietal fontanels well developed; mouth small; teeth 
wanting; eyes covered by a transparent membrane; scales small, cycloid; 
lateral line complete; no caudal fin; origin of anal about the length of 
pectoral fin behind vertical from gill-opening. 
51. Hypopomus brevirostris (Steindachner). 
Rhamphichthys brevirosiris Steindachner, Sitzb. K. Ak. Wiss. Wien, 
LVIII, 1868, 254, Pl. II, fig. 2 (Guaporé); Ginther, Cat. Fish. 
Brit. Mus., VIII, 1870, 6; Steindachner, Denkschr. K. Ak. Wiss. 
Wien, XLI, 1880, 89 (Rio Guaporé, Amazon stream near San- 
tarem, and Rio Cauca). 
Brachyrhamphichthys brevirostris Eigenmann & Eigenmann, Proc. 
U. S. Nat. Mus., XIV, 1891, 62. 
Hypopomus brevirosiris Eigenmann & Kennedy, Proc. Ac. Nat. Sci. 
Phila., 1903, 530 (Campo Grande, Arroyo Chagalalina); Ellis, 
Memoir. Carnegie Mus., VI, 1913, 134, fig. 7; Eigenmann & Fisher, 
Indiana Univ. Studies, No. 25, 1914, 236 (Rivers of Colombia). 
Hypopomus occidentalis Regan, Ann. & Mag. Nat. Hist., Ser. 8, XIV, 
1914, 32. 
_ Head in length to end of anal fin 6.8 to 9.3; depth 6.8 to 9; A. 213 to 
238. 
Body elongate, rather strongly compressed; caudal filament ribbon- 
shaped, pointed; upper profile of head and body gently convex; head 
short; snout blunt, 3 to 3.55 in head; eye small, covered with a trans- 
parent membrane, 9 to 12 in head; interorbital 4 to 4.35; mouth small; 
jaws subequal, the lower slightly included; maxillary about twice the 
length of eye; teeth wanting; no mental filaments; lateral line becoming 
obscure posteriorly; scales small, cycloid; caudal filament 1.12 to 1.2 in 
length to end of anal; vent under preopercular margin, from 2 to 3.5 
times diameter of eye behind vertical from posterior margin of orbit; 
origin of anal fin a little in advance of tips of pectorals, or about the 
snout’s length behind base of these fins; pectoral fins short, 1.65 to 2 in 
head. 
Color brownish or buff, with darker markings of varying sizes, some- 
times forming more or less distinct cross-bars on anterior portion of 
body. 
This fish is represented by 4 specimens ranging from 68 to 162 mm. 
in length. ‘Two of our specimens are from the Rio Chagres Basin and 
the other two from the Rio Bayano Basin. 
Habitat: Both slopes of Panama and Colombia and south to the 
Rio de la Plata. 
