FAMILY V. CYPRINID^E. 59 



wards; interorbital broad, convex, 3 in head; snout very slightly 

 bluntish, 3^4 in head; eye 3^ to 4^ in head; mouth large, oblique; 

 maxillary reaching vertical from anterior margin of orbit; origir^' 

 dorsal nearer tip of snout than base of caudal; base of dorsal 2^" r ?fT 

 head; its longest ray 1% in head; pectoral long and slender, its length 

 i ^ in head ; ventral i J/ in head ; base of anal 2 % in head ; caudal fin 

 long and pointed; caudal peduncle rather slender, its least depth 2 

 in head; lateral line decurved, complete. 



Color light brownish; a faint plumbeous band on side; no caudal 

 spot; the fins all plain. Length about 10 inches. 



This species is known only from the region about the lake whose 

 name it bears, and where it is abundant. Spawning time the mid- 

 dle or the latter part of June. This fish is much used for food. 



26. Aztecula Jordan & Evermannn. 



Azteca Jordan & Evermann, Bull. 47, U. S. Nat. Mus., 1896, 



258. (Type, Notropis aztecus Woo\ma,n = Codoma vittata Girard.) 



Aztecula Jordan & Evermann, ibid., 1898, 2799; substitute for 



Azteca, which is preoccupied in Entomology. 



Body very robust; moderately compressed; head rather large; 

 snout decurved; mouth terminal, oblique, rather small; fins small; 

 scales small; origin of dorsal slightly behind ventrals; teeth 4-4, no 

 grinding surface, tips slightly hooked; intestinal canal short, about 

 equal to the length of the fish ; gill rakers very short, about 9 on first gill 

 arch; vertebrae 18+16=34. 



KEY TO THE SPECIES OF AZTECULA. 



a. Scales large, about 50 in the lateral line; about PAGE 



23 scales between nape and dorsal fin. 

 b. Eye large, its diameter 3%" in the head ; caudal 



peduncle robust, its least depth 2 in head vittata 59 



bb. Eye smaller, its diameter 5 in the head; 

 caudal peduncle slender, its least depth 2% 



in head lermcs 60 



aa. Scales small, about 59 in the lateral line ; about 



30 scales between nape and dorsal fin mericana 61 



51. Aztecula vittata (Girard). 



Codoma vittata Girard, Proc. Acad. Nat. Sci. Phila., 1856, 195; 



Valley of Mexico: Girard, Mex. Bd. Sur., 53, pi. xxix, figs. 



1 8-2 1, 1859; Valley of Mexico. 

 Notropis aztecus Woolman, Bull. U. S. Fish Comm., 1894, 63 ; Canals 



about the City of Mexico: Jordan & Evermann, Bull. 47, U. S. 



Nat. Mus., 1896, 258; City of Mexico. 



