GAMBUSIA. 95 
middle of eye to free edge of operculum. 29 to 31 scales in a longitudinal series. Dorsal 8-9 ; origin 
usually nearer to posterior end of caudal fin than to tip of snout ; free edge of the finconvex. Anal 9-10, 
similar to the dorsal, ending below or a little in advance of the middle of the dorsal. Pectoral 2-3 the 
length of head. Caudal rounded or subtruncate. Least depth of caudal peduncle about % the length of 
head. Olivaceous ; edges of scales darker; often a dark longitudinal band from upper part of eye to base 
of caudal. 
Hab. Streams of the Atlantic Slope from Illinois to Vera Cruz: 
In Mexico recorded from Rio Chihuahua and Rio Conchos in Chihuahua ?; 
Monclova in Coahuila®?; Monterey and Rio San Diego in Nuevo Leon?; 
Matamoros, Rio Soto la Marina, and Rio Panuco in Tamaulipas? ; Orizaba! and 
Vera Cruz. 
Here described from specimens measuring up to 70 mm. in total length. 
2. Gambusia bonita. 
Gambusia bonita, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 182, fig. 39%. 
Depth of body 34 to 32 in the length, length of head 33 to 33. Snout shorter than eye, the diameter of 
which is 23 to 23 in the length of head. Interorbital width equal to the distance from posterior margin 
of pupil to free edge of operculum. 29 to 31 scales in a longitudinal series. Dorsal 8-10; origin a 
little nearer to posterior end of caudal fin than to tip of snout; middle rays longest. Anal 10-11, 
similar to the dorsal, ending below the anterior rays of dorsal. Pectoral 4 the length of head. Caudal 
rounded or subtruncate. Least depth of caudal peduncle = the length of head. Olivaceous; scales of 
upper part of body with dark edges. 
Hab. Mexico, Rio Papaloapam : 
Refugio 1, Motzorongo!. 
Here described from five specimens, measuring up to 00 mm. in total length, from 
Refugio, received from Dr. Meek. 
3. Gambusia fasciata. 
Gambusia fasciata, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 129, fig. 37°. 
Depth of body 34 to 33 in the length, length of head 4 to 43. Snout a little shorter than eye, the diameter 
of which is 3 to 34 in the length of head. Interorbital width equal to the distance from middle of eye 
to free edge of operculum. 32 scales in a longitudinal series, Dorsal 8; origin considerably nearer to 
end of caudal than to tip of snout; middle rays longest. Anal 9-10, similar to the dorsal, ending below 
the origin of dorsal. Pectoral +the length of head. Caudalsubtruncate. Least depth of caudal peduncle 
2 the length of head. 4 or 5 narrow vertical or slightly oblique blackish bars on each side; a small 
blackish spot on the anterior dorsal rays, another on the anal. 
Hab. Mexico, Oaxaca, Tequesixtlan (Gadow), San Gerdnimo !, Tehuantepec !. 
Here described from six specimens, measuring up to 55 mm. in total length. 
4. Gambusia tridentiger. 
Gambusia tridentiger, Garm. Mem. Mus. Comp. Zool. xix. 1895, p. 89°. 
Inner teeth tricuspid. 28 to 30 scales in a longitudinal series. Dorsal 7-8; origin about equidistant from 
occiput and end of caudal, nearly above the last ray of anal. Anal 10. 7 or 8 brownish vertiéal bars, 
separated by pale interspaces of equal width, on the posterior part of the body. 
Hab. Isthmus of Panama !. 
