10 



NOETH AMERICAN FAUTsTA. 



[No. 40. 



MATERIAL AND ACKNOWLEDGMENTS. 



This revision of the prairie-dogs is based upon a study of 876 speci- 

 mens, akaost all of which are well-prepared skins and skulls.^ A few 

 skeletons and odd skulls also have been examined. The liberal policy 

 of American museums has made it possible to assemble practically 

 all the study material of the group preserved in American collections, 

 including the types and type series. Thanks for these courtesies are 

 especially due Dr. J. A. AUen, American Museum of Natural History; 

 Mr. Samuel Henshaw and Mr. Outram Bangs, Museum of Comparative 

 Zoology; Mr. Edward R. Warren, Colorado Springs, Colo.; and Mr. 

 Charks B. Cory and Mr. W. H. Osgood, Field Museum of Natural 

 History. Mr. Warren's private collection of Colorado specimens of 

 Cynomys leucurus and C, gunnisoni has been of especial value and 

 help. In the lists of specimens examined the source is indicated of 

 all material from localities not represented in the United States Na- 

 tional Museum collections. 



This review is pubhshed as a North American Fauna with the per- 

 mission of the Secretary of the Smithsonian Institution. 



Genus CYNOMYS Rafinesque. 



1817. Cynomys Eafinesque, Amer. Monthly Mag., II, p. 45. 



1819. Monax Warden, Stat., Pol., and Hist. Acc. U. S., I, p. 226. Type, Monax 



missouriensis Warden (= Cynomys ludovidanus). 

 1827. Cynomis Lesson, Manuel de Mamm., p. 244 (pro Cynomys Kafinesque). 

 1894. Cynomomus Osborn, Science, XXIII, p. 103 (pro Cynomys Rafinesque). 

 1899. Mamcynomiscus Herrera, Sin. Vulg. Cient. Vert. Mexicanus, p. 22 (pro 



Cynomys Rafinesque). 



Type species. — Cynomys socialis Rafinesque { = Arctomys ludo- 

 vidana Ord). 



Diagnosis. — Like CiteUus, but with cheek teeth relatively much 

 larger; maxillary tooth rows strongly convergent posteriorly; molari- 

 form teeth with protocone much more hypsodont; and crown of last 

 upper molar with well-developed mesostyle and accompanying 

 additional transverse ridge. 



General characters. — Size as in larger species of CiteUus or grerter; 

 form stout; tail short, rarely more than one-fourth the total length; 

 ears short, not extending beyond fur of winter pelage; cheek pouches 

 moderate. Wrist and heel heavily furred; a tuft of hair in center of 



1 The material examined has been assembled from collections as follows: 



U. S, National Museum, Biological Survey collection 465 



U. S. National Museum proper 221 



American Museum of Natural History , New York , N . Y 81 



Museum of Comparative Zoology, Cambridge, Mass 47 



Collection of E . E . Warren , Colorado Springs , Colo 44 



Field Museum of Natural History, Chicago, 111 18 



Total number of specimens 87Q 



