Hi FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. V. 



it seems strange that a great river like the Balsas which lies wholly 

 within the tropics should contain so few species. This river is fed 

 by many mountain streams, and even in the dry season contains an 

 abundance of clear water. Collections of fishes have been made at 

 eight places in this river basin, and in all only twelve species of fishes 

 have been taken, a number much fewer than one would expect. 



SHORE FISHES WHICH HAVE BECOME MORE OR LESS 

 ESTABLISHED IN THE FRESH WATERS OF MEXICO. 



There has been a tendency in this as in other countries for salt- 

 water fishes to become established in fresh water. Some of these 

 may properly be considered as fresh water species.* The others are 

 properly shore fishes found in fresh water, and usually at a consider- 

 able distance from the sea. Below is given a list of these species : 



Tylosurus marinus (Walbaum) . Dormitator maculatus (Bloch) . 



Thyrina crystallina (Jordan & Culver). Eleotris pisonis (Gruelin). 



Menidia lisa Meek. Eleotris pictus Kner & Steindachner. 



Mugil cephalus Linnaeus. Gobius parvus Meek. 



*Agonostomus monticola (Bancroft). Gobius claytoni Meek. 



Neomugil digueti Vaillant. Chonophorus nelsoni (Evermann)-. 



Joturus pichardi Poey. *Chonophorus taiasica (Liechtenstein) . 



Centropomus mexicanus Bocourt. Chonophorus mexicanus (Gunther). 



Pomadasys templei Meek. Gillichthys detrusus Gilbert & Scofield. 



Pomadasys starri Meek. Achirus mazatlanus (Steindachner). 



*Haploidonotus grunniens Rafinesque. Achirus fonsecensis (Giinther). 



*Philypnus dormitor Lac6pede. Achirus fasciatus Lacepede. 



The species of Chirostoma belong to a salt-water family; they are, 

 however, confined to the Mexican plateau, and cannot be regarded 

 as shore fishes, and so are not included in the foregoing list. 



GAME FISHES OF MEXICO. 



The large-mouthed black bass which is abundant in the streams 

 of northeastern Mexico as far south as the Rio Soto la Marina, and 

 the trout in the mountain streams of the Pacific slope in Sonora Chi- 

 huahua and Durango are the only fishes in northern Mexico which 

 can properly be called game fishes. Each of these species is confined 

 to a rather small area. In the streams of southern Mexico there are 

 no game fishes. The Cichlids are abundant, but will not take the 

 hook in a manner that would best please the professional angler. 

 There are in these southern streams a species of Centropomus and two 

 of Pomadasys, usually called by the natives Roballo, which are 

 regarded as game fishes. They are not properly fresh-water fishes, 



