May, igo2. The IcHTHNoi.cxiv ok Mkxico — AIi-.kk. 115 



Mexico. It is one of the largest species of the genus, though it 

 seldom reaches a length of 12 inches. Specimens from Lago 

 de Chalco are very dark, while those from Lago de Patzcuaro are 

 very light and translucent. Specimens from Lago de Xochomil- 

 cho are intermediate. Scales entire: gill-rakers 5-1-13=18; verte- 

 bras 23-j-ig=r42; teeth small, in a narrow band in upper jaw, in 

 two series in the lower. There are often with a few large" teeth 

 oh the vomer, as in C. estor. 



The ovaries not well developed; eggs small, spawning season 

 evidently late in the summer. Chalco; Xochomilcho; Patzcuaro. 



Chirostoma chapalae Jordan & Snyder. 



This species is very white and translucent. It is'a small spe- 

 cies, seldom reaching a length of 4 inches. Edges of scales 

 crenate; gill-rakers 6-1-24 = 30; vertebrae 24-1-20 = 44. \'ery abun- 

 dant in Lago de Chapala. Ocotlan; La Palma. 



Chirostoma grandocule Steindachner, 



Edges of scales crenate; base of anal fin i }j in ^length of the 

 head, its rays ig; snout 3| in head; mandible 2?^; eye 3?5; teeth 

 minute, in narrow bands on each jaw, approaching two series 

 laterally; gill-rakers 5-1-22 = 27; vertebrae 23-1-20=43; species of 

 small size, the largest specimens about \\ inches. This appears 

 to be the most abundant Chirostoma in Patzcuaro Lake. Ocotlan; 

 La Palma; Patzcuaro. 



Chirostoma promelas Jordan cK: Snyder. 



This is the only species of Chirostoma so far known which has 

 the upper jaw decidedly longer than the lower. The tip of the 

 snout is black, otherwise the color is light and translucent. 

 Edges of scales crenate; gill-rakers 5-|-ig = 24. This species is not 

 abundant; size medium. Our largest specimen is 4^ inches in 

 length. The longest specimen collected by Jordan.c\: Snyder is 7 

 inches in length. Ocotlan; La Palma. 



Chirostoma lucius Boulenger. 



This is evidently the species described by Jordan cV Snyder as 

 C. crystalinum in a foot-note "■•■ Dr. Jordan expressed the opinion 

 that C. lucitis is identical with C. Icrmce.. The teeth of C. luciiis 

 are described as small, while C. lertnce has very large strong teeth. 



(* Bui. U.S. F. C. lO.'iO. i-Al.\ ■ 



