Family V. Cyprinid^. 49 



Hybognathiis melanops Jordan, Bull. U. S. Geol. Sur., 1878, 402; 

 Brownsville, Texas: Woolman, Bull. U. S. Fish Comm., 1894, 

 59; Rio Conchos, Chihuahua: Jordan & Evermann, Bull. 47, 

 U. S. Nat. Mus., 1896, 217: Meek, Field Col. Mus. Pub. 65, 

 1902, 77; Chihuahua, Jimenez. 



Hybognathiis punctifei Garman, Bull. Mus. Comp. Zool., 1881, 

 89; Parras, and Spring near Saltillo, Coahuila, Mexico. 



Hybognathiis civilis Cope, Trans. Amer. Phila. Soc, 1884, 167; 

 Monterey, Nuevo Leon. 



Hybognathiis episcopa Jordan & Evermann, Bull. 47, U. S. Nat. 

 Mus., 1896, 214. 



Hybognathiis amara Jordan & Evermann, Bull. 47, U. S. Nat. 

 Mus., 1896, 215. 



Southern Texas and northern Mexico south to the Rio Mezquital 

 in Durango, and the Rio San Juan, in Nuevo Leon. (Labor; Durango; 

 Monterey; Montemorelos.) 



Head 4; depth 3^; D. 8; A. 7; scales 7-38 to 45-5. Body rather 

 stout, moderately compressed; head moderate, flattish above; snout 

 bluntish, 3^; interorbital width 2 in head; eye 3^; mouth small, 

 oblique; maxillary reaching about half-way to vertical of front of 

 eye; margin of upper lip on a level with lower margin of pupil; 

 pharyngeal teeth 4-4, grinding surface not hooked, sometimes the 

 distal portion blackish; origin of dorsal midway between base of 

 caudal and nostril; longest dorsal ray 1^ in head; base of dorsal 2 in 

 head; length of pectoral 1% in head; ventral \% in head; lateral 

 line slightly decurved, occasionally missing on a few scales; caudal 

 peduncle rather strong, its least width about 2 in head (caudal 

 peduncle in Durango specimen is about 2\ in head and in Chihuahua 

 specimens about 2 in head) ; alimentary canal about three times the 

 length of the body; peritoneum black. 



Color dark to light brownish (specimens from Montemorelos con- 

 siderably paler), lighter below; edges of scales darker, forming dark 

 lines along their rows; in darker specimens a dark lateral band 

 ending in a dark caudal spot; in paler specimens this band and spot 

 very faint; fins all plain. Length about 3 inches. Southern Texas 

 and northern Mexico, south to the Rio Mezquital, Durango, and 

 the Rio San Juan, Montemorelos. 



This species is very variable. I have compared many specimens 

 from various localities in Mexico and regard all as belonging to the 

 same species. The specimens taken at Durango and Monterey are 

 much darker than those from Montemorelos; the color of specimens 

 from other localities represent various shades between these extremes. 

 Spawning time the last of May and first part of June. 



