Vol. XVII, pp. 55-77 March 2 i . 1 904 



PROCEEDINGS 



OF Till': 



BIOLOGICAL SOCIETY OF WASHINGTON . 



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THIRTY NEW MICE OF THE GENUS PEROMYSCUS 

 FROM MEXICO AND GUATEMALA. 



BY WILFRED H. OSGOOD. 



The mice of the genus Peromyscas, so well represented in the 

 United States and so well known for their numerous specific 

 and subspecific variations, reach their highest development 

 south of our borders in Mexico. This is the region of their 

 greatest abundance, both in actual numbers and in specific 

 tyi)es. Some are closely related to forms found in the United 

 States, but the majority are entirely different. 



The thorough work of E. W. Nelson and E. A. Goldman in this 

 region has resulted in the acquisition of ver}^ large numbers of 

 specimens of this genus, and now for the first time it is possible 

 to learn the numlier and diversity of their specific and sub- 

 si)ecific forms. S})ecimens of Per amy sens, from Mexico and 

 Guatemala alone, to the number of nearly 3,400, are now in the 

 collection of the U. S. Biological Survey. This is unquestion- 

 ably in excess of the combined number in all other collections 

 in the world, and it is therefore not surprising that a compara- 

 tively large number of new forms should be found among them. 



The descriptions herewith are presented in advance of a 

 revision of the entire genus, now in preparation, in which it 

 is hoped that all the known forms may be fuU}'^ discussed. 



I take pleasure in making acknowledgments to Dr. C. Hart 

 Merriam, to whom I owe the opportunity of elaborating this 



C— Proc. Biul. Soc. W'abu. Vol. XVII, I'joi (55) 



