326 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. 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 Peecilia pittieri from Costa Rica. 



41. Genus Mollienisia LeSueur. 



Mollienisia LeSueur, Jour. Acad. Nat. Sci. Phila., 1821, 3, PI. Ill (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 1 6 

 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; vertebrae about 



KEY TO THE SPECIES. 



a. Dorsal fin with 7 to 1 1 rays. 



b. Origin of dorsal slightly in advance of anal. 



c. Dorsal fin with 10 or n rays; anal with 10 rays; dorsal and 

 caudal fins spotted with black. sphenops, p. 326. 



cc. 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. 329. 



bb. Origin of dorsal slightly behind that of anal; dorsal and caudal 

 with a series of transverse spots. cuneata, p. 329. 



aa. Dorsal rays n to 13; origin of dorsal a little nearer base of 

 caudal than end of snout. formosa, p. 330. 



63. Mollienisia sphenops (Cuvier & Valenciennes). Paribiba. 

 Pcecilia sphenops Cuvier & Valenciennes, Hist. Nat. Poiss., XVIII, 1846, 



130, PI. 526 (Vera Cruz, Mexico); Gtinther, 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., Zool. Ser., X, 1912, 71. 



