100 HAPLOMI. 
Hab. Sovutnzrn Mexico, Otopa!, Motzorongo}, Venta Salada}, El Hule?, Perez}, and 
Cuicatlan! in Vera Cruz, Oaxaca!, Tequesixtlan (Gadow), San Gerdnimo? and 
Tehuantepec in Oaxaca. 
Numerous examples, measuring up to 80 mm. in total length. 
3. Girardinus pleurospilus. 
Girardinus pleurospilus, Giinth. Cat. Fish. vi. p. 855 (1866) *, and Trans. Zool. Soc. vi. 1868, 
p. 486, t. 87. fig. 1%. 
Heterandria pleurospilus, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 658”. 
A series of from four to eight rounded dark spots, each about as large as the eye, along the middle of 
the side. 
Hab. GuateMaua, Lake of Duefias!2, Lake Nacasil (Salvin). 
Numerous examples, measuring up to 60 mm. in total length. 
13. PQECILIA, Schneider, 1801. 
Pecilia, Gunth. Cat. Fish. vi. p. 839 (1866); Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, 
p. 690. 
Viviparous. Anal fin, in the male, advanced and modified into an intromittent organ of moderate length. 
Mouth small, transverse ; rami of lower jaw weakly connected; minute teeth in bands, with an outer 
series of more or less enlarged, curved, unicuspid, movable teeth. Dorsal fin with 8 to 11 rays, higher 
but not much longer in the males than in the females. Caudal rounded or subtruncate in both sexes. 
Hab. Mexico and Central America to Brazil; West Indies. 
P. elongata is known to enter the sea, and probably P. sphenops, which is abundant 
in brackish water, does so also. 
Dr. Garman, in his monograph of the Cyprinodonts (Mem. Mus. Comp. Zool. xix. 
1895), proposed a considerable reduction in the number of Mexican and Central- 
American species of this genus. He placed P. couchiana, Girard, P. mexicana, 
Steind., P. thermalis, Steind., P. petenensis, Giinth., P. dovii, Giinth., P. spilurus, 
Ginth., and P. dutleri, Jord., in the synonymy of P. sphenops, Cuv. & Val., and 
P. elongata, Giinth., P. boucardi, Steind., and P. chisoyensis, Giinth., in the synonymy 
of P. gilliz, Kner & Steind. 
After examination of a large number of specimens I have reached the conclusion 
that P. couchiana, P. petenensis, P. spilurus, and P. elongata are very distinct and 
easily definable species. The others enumerated appear to be merely forms of one 
widely distributed and variable form, P. sphenops. 
