VOL. XV, PP. 101-116 JUNE 2, 1902 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



SYNOPSIS OF THE NORTH AMERICAN SPECIES 

 OF SIGMODON. 



BY VERNON BAILEY. 



The present brief synopsis of the North American species of 

 Sigmodon, commonly known as cotton rats, is the outgrowth 

 of an attempt to work out the distribution of the several forms 

 occurring in the state of Texas. In this connection it became 

 necessary to make a critical study of the group, which has re 

 sulted in the recognition of 21 apparently valid forms, 10 of 

 which are here described for the first time. A long discarded 

 name, berlandieri, is reinstated, and two recent names are 

 placed in synonymy. Of the 21 species and subspecies, 9 occur 

 in the southern United States; the others are scattered over 

 Mexico and Central America. Of the four species described 

 from northern South America I have seen no specimens. The 

 names and type localities are as follows: Sigmodon sanctcemar- 

 tce Bangs, from Pueblo Viejo, Colombia; Sigmodon bogotensis 

 Allen, from Plains of Bogota, Colombia; Sigmodon peruanus 

 Allen, from Trujillo, Peru; Sigmodon simonsi Allen, from 

 ]Eten, coast of northwest Peru. 



The material on which the conclusions are based consists of 

 23-BioL. Soo. WASH. VOL. XV, 1903, (101) 



