May, igo2. The Ich i-hvologv ok Mexico — Mekk. 77 



CYPRINID.^. 

 Campostoma ornatum (jirard. 



Eggs in temalcs from Chihuahua not much developed, not 

 enough to give any definite idea as to time of spawning season. 

 All of the specimens of this species were collected during the last 

 half of June. 



Very abundant in Northern Mexico, in the head waters of the 

 Atlantic and Pacific coast streams. 



Taken by me as follows: Colonia Juarez; Chihuahua: San 

 Andres: Santa Rosalia: Jimenez; Miiiaca. 



Hybognatlius melanops (Girard). 



Head 4: depth 3^; Eye equals snout, 3^ in head. Scales 41 

 to 45. Origin of dorsal slightly nearer base of caudal than tip 

 of snout. Dark brown color, edges of scales darker, forming 

 • longitudinal lines along rows of scales. The entire body covered 

 with minute dark dots. A dark lateral band ending in a black 

 caudal spot; this is indistinct in the larger and darker speci- 

 mens. Largest specimen 2.50 inches. Ovaries slightly devel- 

 oped. Spawning season about August. Abundant. Chihuahua; 

 Jimenez. 



Algansea tincella (Cuv. & Val). 



This is a very variable species. Those from the lakes about 

 the City of Mexico are very robust and have a rather short caudal 

 fin. The gill-rakers are very short, 3-I-12. The scales range 

 from 65 to 70. Specimens from San Juan del Rio are rather slen- 

 der and have a longer and more pointed caudal fin. In this 

 respect these specimens are not unlike those from Celaya, and 

 Aguas Calientes. In all of these the gill-rakers are short and 

 not more than 15 in number. Vertebrae 20-1-17 = 37. 



The black caudal spot is well defined in the smallest specimens 

 from all of the localities, though on individuals about <S inches in 

 length from Lago de Chalco it is undistinct or absent. 



Drs. Jordan and Evermann regard A. ^?//j7/-(?/<,' as a synonym 

 of A. sallei. I do not believe this is correct. The latter species 

 belongs to a river basin which has a different fauna. The speci- 

 mens described by Dr. Jordan are not in good condition. Mr. 

 Bean, who kindl}- re-examined the types of A. ausirale, believes it 

 had more than 60 scales in the lateral line. Dr. Gunther's 

 locality for A. sai/ci may be wrong. 



