326 Fretp Museum or Naturat History — Zoétocy, Vor. X. 
midway between the tip of the snout and base of caudal, or nearer the 
former; the modified anal reaching quite to caudal fin. 
Color olivaceous, scales dark edged; a blackish spot above the vent; 
fins dusky, the dorsal with a blackish basal band and a dark edge. The 
male with indistinct cross-bars on the body. Females 35 to 60 mm. 
in length; males 35 to 42. 
This species was not taken by us at Colon. It is probably identical 
with the species described by Meek* as Pacilia pittiert from Costa Rica. 
41. Genus Mollienisia LeSueur. 
Mollienisia LeSueur, Jour. Acad. Nat. Sci. Phila., 1821, 3, Pl. III (type | 
Mollienisia latipinna LeSueur). 
Body oblong to rather robust; mouth small, transverse, with weak 
jaws; teeth small, in bands, the outer series in each jaw movable; 
branchiostegals 5; anal fin of female slightly in advance to slightly 
behind dorsal; dorsal fin of males often very high; dorsal fin of 7 to 16 
rays; anal fin of male modified into an intromittent organ, the first 
prolonged ray bearing a small antrorse spine at or near its end, the last 
ray bearing a process directed outward and towards the base of the fin; 
intestinal canal long and with numerous convolutions; vertebre about 
17+18. 
KEY TO THE SPECIES. 
a. Dorsal fin with 7 to 11 rays. 
b. Origin of dorsal slightly in advance of anal. 
c. Dorsal fin with 1o or 11 rays; anal with 1o rays; dorsal and 
caudal fins spotted with black. sphenops, p. 326. 
ce. Dorsal fin with 7 or 8 rays; anal fin with 8 or 9 rays; dorsal fin 
with a dark spot on its base, the rest of dorsal and caudal fin 
unspotted. caucana, p. 320. 
bb. Origin of dorsal slightly behind that of anal; dorsal and caudal 
with a series of transverse spots. cuneata, p. 320. 
aa. Dorsal rays 11 to 13; origin of dorsal a little nearer base of 
caudal than end of snout. formosa, p. 33°. 
63. Mollienisia sphenops (Cuvier & Valenciennes). Paribiba. 
Pacilia sphenops Cuvier & Valenciennes, Hist. Nat. Poiss., XVIII, 1846, 
130, Pl. 526 (Vera Cruz, Mexico); Gunther, Cat. Fish. Brit. Mus., 
VI, 1866, 343 (Vera Cruz, Mexico); Jordan & Evermann, Bull. 
U.S. Nat. Mus., XLVII, 1896, 694; Regan, Biol. Cent. Amer., 
Pisces, 1907, 102 (Streams near Panama). 
*Meek, Field Mus. Nat. Hist. Pub., Zodl. Ser., X, 1912, 71. 
