8 -REPORT ON A COLLECTION OF FISHES FROM THE RIVERS OF 
CENTRAL AND NORTHERN MEXICO. 
By albert J. WOOLMAN, 
111 the suuimei' of 1891 the writer was a member of a jiarty which, umler the 
direction of Dr. J. T. Scovell, of Terre Haute, lud., traversed the northeastern and 
central parts of Mexico for the purpose of making certain studies of Mount Orizaba. 
With the assistance of Mr. Ulysses O. Cox, of Mankato, Minn., collections of fishes 
were made in the mountain streams at intervals between Ei Paso, Tex., and Orizaba, 
Mexico. A list of the species obtained and notes on the same are given in the 
present paper. 
In mountainous regions the number of species of fishes is small, and this is 
especially true in Mexico, Avhere the streams are short, their basins isolated, and the 
volume of water varying greatly from one season to another. The present collection 
contains twenty-four species of fishes, and, although small, it is of unusual interest, 
as six of the species obtained and one genus were new to science. As the entire col- 
lection was made in the headwaters of the streams all the forms obtained are strictly 
fresh- water species. 
Seven families are represented in the collection. Of those taken south of the Rio 
Grande, nearly 50 per cent are CyjnHnidxe and 30 per cent Cyjirinodontidcc, while the 
remaining 30 per cent are divided among five other families; the Fercidm have two 
representatives in the genus Idtheostoma, the only spiny-rayed fishes obtained; the 
Catostomidw, Sihtridce, Gharaeinidw, and Athermidce are each represented by a single 
species. 
A notable feature of the fishes of this region is the uniformity in the teeth of the 
Cyprinidce, the dental formula in almost every case being 0, 4—1, 0. The scales of 
Mexican species are, as a rule, smaller than those of the related species taken farther 
north. Variability and richness of color are also more pronounced. 
The writer is indebted to Dr. David S. Jordan, president of Lelaud Stanford 
^ Junior University, and Dr. Carl H. Eigeumanu, professor of geology, University of 
Indiana, for assistance and suggestions in the preparation of this paj^er. Duplicate 
specimens of the species obtained are deposited in the U. S. National Museum, at 
'Washington, D. C., in the museums of Lelaud Stanford Junior University and the 
Indiana University, and in the British Museum, London, England. 
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