FISHES OF THE COLORADO BASIN. 
475 
7. Eleven nominal species collected in Colorado and Utah in 1889 by Dr. David 
S, Jordan, Prof, Barton W. Evermann, Mr. Bert Fesler, and Mr. Bradley M. Davis. 
These were reported ni)on by Dr. Jordan in 1890. 
8. One species [Gila rohusta) collected in Babacomari Creek near Fort ITuachuca, 
Ariz., in May, 1892, by Dr. A. K. Fisher, to whom we are indebted for the pilvilege of 
examining these and other fishes collected by him. 
9. Seven species obtained by the i)reseiit writers from Green Elver at Green River, 
Wyo., in 1893. The report upon these species is contained in this paper. 
10. Collections have recently been made at Yuma and elsewhere in Arizona by 
Dr. Charles H. Gilbert, but other than describing one new species he has not yet 
published the results. 
The fish fauna of the Colorado Basin is not rich in number of species, the total 
number no’w recognized being but 32 native species. These represent 5 families and 
18 genera, as follows: 
Catostomidw, 8 species: Pantosteus, 3; Catos tomus^ 3; Xi/rauchen, 2. 
Cyprinidee, 19 species: Ptycdiocheihis,!-, GiIa,o-, Leiiciscus, 4z-, Tiaroya,!-, Ehin- 
iclitJiySj 1; Agosia,4:-, Couesius, Ij Lepidomeda, 2; Meda,!-, Playopterus, 1. 
Salmunida’, 2 species: Salma, 1; Coregonus, 1. 
Poeciliidcv, 2: Cyprinodon, 1; Meterandria, 1. 
Cottida'., 1: Cottas, 1. 
Though the families and species constituting the fish fauna are very few, they are 
of unusual interest to the student of geographic distribution. 
The Cypriuidm, or minnow family, is by far the most imiiortant family as to the 
number of species, embracing as it does almost 60 per cent of the entire number. The 
Catostomidae, or sucker fainily, comes next, Avith 8 species, or 25 per emit of the total 
number. Of the 18 genera, Xyrauchen, Gila, Tiuroga, Meda, and Flagopterus are thus far 
known only from the Colorado Basin; Lepidomeda was not known to occur elsewhere, 
until recently discovered by Dr. Gilbert among the fishes collected in the Great Basin 
in southwestern Nevada by the Death Valley expedition; Ptychochcilus is a Pacific 
Coast genus, represented in most of the larger streams of California, Oregon, and 
Washington ; Pantosteus, Agosia, and Meterandria, as now' limited, are genera of rather 
wide distribution in the western part of the United States; while the 8 remaining 
genera are found throughout middle North America. 
Of the 32 species, all but 7 are thus far known only from this basin. The 7 species 
wdiich are not confined to the Colorado Basin are the Utah chub {Leiiciscus Uneatus), 
the western dace {Rhinichthys cataractw dulcis), Agosia chrysogaster, Williamson’s 
whitefish, the blob, Lepidomeda vittata, and Girardinus macularius. The home of the 
Utah chub is in the Utah and Upper Snake River basins. The western dace belongs 
in the lieadAvaters of the Missouri, Platte, Arkansas, and Rio Grande, and in the 
Utah and Columbia basins. Williamson’s whitefish and the blob occur in the head- 
waters of all of our Avestern rivers. Lepidomeda vittata, the fifth species, has been 
taken only once outside of the Colorado Basin. It is thus seen that over 78 per cent 
of the species of fishes iioay knoAvn from the Colorado Basin are peculiar to it. This 
is a larger percentage of species peculiar to a single river basin than is found 
elsewhere in North America. 
