UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



MONOGRAPHS 



NORTH AMERICAN 



RODENTIA. 



ELLIOTT COUES, 



CAPTAIN AND ASSISTANT SUliGKON UNITED STATES ARMY, 

 SECRETARY AND NATURALIST or TTIB SURVEY; 



JOEL ASAPH ALLEN, 



ASSISTANT IN THE MUSEUM O!" COMPARATIVE ZOOLOGY, CAMBRIDGE, 

 SPECIAL COLLABORATOR OF THE SURVEY. 



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c 



WASHINGTON: 



GOVERNMENT PRINTING OFFICE 

 1 S 7 7 . 



