May, igo2. Thf. Ichthvolixjv of Mexico — Mkkk. 99 



One female specimen 1.91 inches in lengtli contained 30 

 eggs in which the eyes and outline of young were formed. 



A second female from Jimenez, 1.90 inches in length, con- 

 tained 25 similar eggs, diameter of eggs -^-^ of an inch. Abundant. 

 Jimenez: Chihuahua: Santa Rosalia: San Andres. 



Gambusia infans Woolman. 



This species is much like G. affinis. It has a shorter head 

 and larger scales, and is usually a little darker in color. Alimen- 

 tary canal i^ times the total length of the body; peritoneum 

 black. One female from Ocotlan contained 15 large eggs in 

 which the eyes and outline of the body were formed. A female 

 1.85 inches in length from Huingo contained 19 large eggs 

 in which the eyes and outline of body of young were formed, 

 34 eggs not at all hatched, each ^-^ inch in diameter, and 12 very 

 small eggs, each about gV, inch in diameter. 



The specimens from Huingo are lighter in color than those 

 from Ocotlan. A few small males were taken at Huingo, these 

 are black, with the tip of the caudal yellow. Two males were 

 taken at Celaya; one of these is black, and the other one has 

 the color of the females. Length of males 1.05 inches. 



Specimens from Huingo were taken May 26; from Celaya, May 

 28, and from Ocotlan June 2 and 3. The spawning time for this 

 species is evidently about the middle of June. 



The origin of the dorsal fin in the female of this species is well 

 behind that of the anal. This is the only Gambusia so far known 

 from Central Mexico. It has been found only in the Lerma 

 Basin. Celaya: La Barca; Ocotlan; Huingo. 



Gambusia gracilis Heckel. 



This species is very different from G. it.fans and G. afflnis. 

 It has a dark lateral band made up of short irregular cross bars. 

 The dorsal fin is also more posterior than in the other two spe- 

 cies. With some doubt I identify our specimens with G. gracilis, 

 J which was originally described from Orizaba, Mexico. 



One female, 1.66 inches in length, from Balsas, contained 

 31 young, each coiled around the egg, 21 eggs in which eye spots 

 were present, 15 large eggs without eye spots, and 8 small eggs. 

 The large eggs are about ,'- inch in diameter. This specimen 

 was collected April 22. Spawning time evidently early in May. 

 The males are 1.19 inches in length, being much smaller than the 

 female. . Taken by us at Balsas and at Puente de Ixtla. 



