ioo FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



KKY TO THK MKX1CAN Sl'KCIKS OK (iAMBUSIA. 



a. Body without a dark lateral band made up of short vertical 

 bars; origin of dorsal fin over middle of anal, and slightly nearer base 

 of caudal than base of pectoral fin. 



/'. Scales in the lateral line 30; head 3^ to 3^ in the length of 

 the body. AITINIS. 



/'/'. Scales in the lateral line 26: head 4! in the length of the body. 



INFANS, 



aa. Body with a dark lateral band, made up of short vertical 

 bars: origin of dorsal behind origin of anal fin, its origin midway 

 between base of caudal and middle of pectoral fin; scales 29. 



GRACILIS. 



GOODEA Jordan. 



The genus Goodca was proposed by Jordan in 1879. It was based 

 on G. atripinnis, a Fundulus-like fish taken from a salt lake in a vol- 

 canic basin near Guanajuato, Mexico. The teeth were erroneously 

 described as tricuspid. In 1900 Jordan and Snyder proposed the 

 genus Xenendum to include the Fundulus-like species with long intes- 

 tines and bicuspid teeth. At my request Mr. B. A. Bean re-examined 

 the dentition of the types of Goodea atripinnis and found the teeth 

 were bicuspid. He also kindly sent one of the cotypes to the Field 

 Columbian Museum. In all of the specimens the teeth are decidedly 

 bicuspid. The genus Xenendum therefore becomes a synonym of 

 Goodca. Gill-rakers long and slender, 37 to 40 on the first gill-arch. 

 Vertebr;i> 19+17 = 36. Outer series of teeth bicuspid; behind these 

 are villitorm teeth. 



Goodea caliente (Jordan & Snyder). 



This species appears to be very widely distributed, being 

 found over a large portion of the Lerma Basin, as well as in the 

 Rio Moctezuma, a river which empties its water into the Atlantic. 

 It inhabits the rivers and smaller lakes. 



The specimens from Lake Quitzeo are very light in color, a 

 feature characteristic of all the fishes taken from this and Patz- 

 cuaro Lake. Specimens from other places are quite dark, 

 especially is this true of those taken from the streams. 



The color of the male is more uniform than that of the female. 

 The young are speckled with brownish, much resembling the 

 young of Zoogoneticus rohustns and the young of Charocodon 

 varidtus. 



The dorsal of the male is considerably higher than that of the 



