THE FISHES OF MOHAVE RIVER, CALIFORNIA. 



By John Otterbein wSnyder, 



Of Stanford University, California. 



The Mohave River has its origin in the San Bernardino Mountains 

 of southern California, Its tributaries drain a relatively small area 

 of the northern slopes of the ranges which separate its basin from 

 that of the Santa Ana River. It flows down the mountains and 

 almost directly across the Mohave desert, where its dwindling current 

 is at length consumed by evaporation or absorbed by the dry earth. 

 Throughout the greater part of its course it receives no addition to 

 its volume except the water of an occasional spring. 



Relief maps do not seem to indicate that the river ever had an out- 

 let in the direction of its course, the sink where it disappears lying in 

 a depression which is mostly surrounded by low mountains except 

 where the river enters. From the San Joaquin basin the Mohave is 

 separated by the high mountains which connect the southern Sierras 

 with the Coast Ranges; besides, a wide expanse of desert intervenes 

 between these mountains and the river channel. The flow of the 

 Mohave is rather fluctuating and uncertain, sudden desert storms and 

 long dry periods contributing in turn to an inconstant river volume. 



The fishes of the Mohave River belong to a single species,^ a member 

 of the genus Siphateles,^ a channel and lake minnow which occurs in 

 the Sacramento-San Joaquin, Klamath, Oregon Lake, Columbia, and 

 Lahontan systems, and Owens River. The species of this group are 

 very closely related, intergradation of distinctive characters being not 

 unusual. In a measure they resemble geographic races or subspecies 

 of birds and mammals as usually defined, except that being fluvial 

 and lacustrine forms, the range of each is definitely circumscribed, 

 and no intermingling or interbreeding of individuals of different forms 

 is possible. Species of Siphateles are not known from Santa Ana or 

 Colorado rivers. 



The Mohave species was recorded by Girard in 1856 as Algansea 

 formosa.^ It was then identified with examples of the genus from 

 Merced (Mercede) River, a tributary of the San Joaquin, and until 

 recently the species was regarded as synonymous with Hesperoleucus 



' The river has not been thoroughly searched for fishes. A collection made near Victor by Mr. Clarence H. 

 Kennedy, and some specimens secured by Mr. Dane Coolidge at Barstow have served as a basis for these notes. 



« Bull. Bureau Fish., vol. 35, 1915-16, p. 60. 



» Proc. Acad. Sci. Phila., 1856, p. 183. Cotypes of Algansea formosa are in the U. S. National 

 Museum, No. 196 from Merced River, and 197 from Mohave River. They are not well enough preserved 

 for careful comparison, although they serve to show without doubt what species the author described. 

 Merced River is the first locality mentioned, and therefore the name /ormoso may be retained for the Sac- 

 ramento-San Joaquin form. 



Proceedings U. S. National Museum, Vol. 54-No. 2236. 



297 



