xxxiv FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. V. 



end of the dry season there is no water in its bed and little or none 

 in the river below Lefdo. The Rio Nieves is south of the Rio Nazas 

 and flows into Lago de Parras, which is only a few miles south of Lago 

 de Mayran. It is very probable that at some former time these two 

 streams united near here, and flowed north into the Rio Grande near 

 the border line between the States of Chihuahua and Coahuila. 



Below is a list of the fishes known from these rivers: 

 Amiurus price! (Rutter) : Lerdo. 

 Carpiodes tumidus Baird & Girard: San Pedro. 



Pantosteus plebeius (Baird & Girard) : Lerdo; Santiago Papasquiaro; Rio Nazas. 

 Campostoma ornatum Girard: Santiago Papasquiaro. 

 Hybognathus episcopus (Girard) : Parras. 

 Stypodon signifer Garman: Lago de Parras. 



Leuciscus nigrescens (Girard) : Lerdo; Santiago Papasquiaro; Rio Nazas; Parras. 

 Nototropis ornatus (Girard) : Santiago Papasquiaro. 

 Nototropis nazas Meek: Santiago Papasquiaro. 



Nototropis garmani (Jordan): Parras; Lerdo; Santiago Papasquiaro. 

 Tetragonopterus mexicanus Filippi: Lago del Muerto; Lerdo; Santiago Papas- 

 quiaro. 



Characodon garmani Jordan & Evermann: Parras. 

 Cyprinodon latifasciatus Garman : Parras. 

 Etheostoma pottsii (Girard) : Santiago Papasquiaro. 



RIO CONCHAS SYSTEM. 



This river drains only a small area east of the Sierra Madre 

 and south of the lower portion of the Rio Grande. The city of 

 Linares is situated between two branches of the stream ; both of these 

 branches contain, by the end of the dry season, only a small amount 

 of water. The following is the list of fishes known from this river 

 system. Amiurus lupus (Girard) and Neetroplus carpintis J. & S. 

 were taken only in the stream north of the city ; all the other species 

 were taken in both streams. 



Amiurus lupus (Girard) : Linares. 

 Carpiodes elongatus Meek: Linares. 

 Myzostoma congestum (Baird & Girard) : Linares. 

 Nototropis lutrensis (Baird & Girard) : Linares. 

 Hybopsis aestivalis (Girard) : Linares. 

 Tetragonopterus mexicanus Filippi: Linares. 

 Fundulus similis (Baird & Girard) : Linares. 

 Poacilia sphenops (Cuvier & Valenciennes) : Linares. 

 Micropterus salmonoides (Lacepede) : Linares. 

 Cichlasoma cyanoguttatum (Baird & Girard) : Linares. 

 Neetroplus carpintis Jordan & Snyder: Linares. 



RIO SOTO LA MARINA SYSTEM. 



This river and its tributaries drain a comparatively small area 

 east of the Sierra Madre Mountains and between the Rio Conchas and 



