Dec. 28, 1916. FIsHEs or PANAMA— MEEK AND HILDEBRAND. 329 
64. Mollienisia caucana (Steindachner). 
Girardinus caucanus Steindachner, Denkschr. K. Ak. Wiss. Wien, XLII, 
1880, 87, Pl. VI, figs. 4 & 5 (Caceres, Colombia), and Denkschr. K. 
Ak. Wiss. Wien, LXXII, 1902, 146 (Baranquilla, Colombia). 
Pecilia caucana Regan, Biol. Cent. Amer., Pisces, 1908, 190. 
Mollienisia sphenops Regan, Proc. Zool. Soc. London, 1913, 1012 (in 
part). 
Head 3.35 to 3.7; depth 3.6 to 4; D. 7 or 8; A. 8 or 9; scales 28 
to 30. 
Body compressed; head slightly depressed, flat above; snout rather 
broad, 3.2 to 4.4 in head; eye 3 to 3.75; interorbital 2.3 to 2.7; mouth 
small, the cleft transverse; teeth and scales as in preceding species; 
origin of dorsal in female over origin of anal, a little nearer end of snout 
than tip of caudal; slightly more anteriorly situated in male; caudal fin 
scaly at basé, the margin rounded; anal fin in female inserted a little 
nearer end of snout than tip of caudal; in the male this fin is inserted 
somewhat nearer end of snout than base of caudal, the modified portion 
usually about equal to length of head, its structure apparently identical 
with that of the preceding species; ventral fins in females reaching vent, 
the outer ray produced in males, reaching beyond base of anal; pectoral 
fins moderate, 1.2 to 1.66 in head. 
Color of the sexes similar, olivaceous; dorsal fin with a dark blotch 
at base of the middle rays; fins otherwise unmarked. 
This species is represented by 22 specimens in the present collection. 
The largest female is 35 and the largest male 30 mm. in length. It 
was taken by us at only two places, Aruza and Cituro, in the Rio Tuyra 
Basin. This is the only species of Mollienisia collected in that river 
basin. 
This species is apparently closely related to M. sphenops, but differs 
in color, and in the number of dorsal and anal rays. 
Habitat: Pacific slope of southeastern Panama and the eastern 
slope of Colombia. 
65. Mollienisia cuneata (Garman). 
Pecilia cuneata Garman, Mem. Mus. Comp. Zool., XIX, 1895, 62, Pl. V, 
fig. 3 (Turbo, Gulf of Darien). 
Head 4; D. 8 to 10; A. 9 or 10; scales 28 or 29. 
Body short and deep; caudal peduncle deep; head depressed, broad 
and flat; snout as long as eye; mouth wide, the jaws weak and loosely 
joined; outer series of teeth slender, oar-shaped, movable; inner bands 
small, pointed; eye half interorbital space, its length 314 in head; origin 
of dorsal over third ray of anal, midway from base of caudal to head: 
