VOL. XVII, PP. 53-54 MA&CH 21, 1904 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



HAPLOMYLOMYS, A NEW SUBGENUS OF PEROMYSCUS. 

 BY WILFRED H. OSGOOD. 



The genus Peromyscus, as at present recognized, contains a 

 larger number of species than any other North American genus 

 of mammals. It has a comparatively wide range, and, although 

 subject to numerous minor variations, preserves its essential 

 characters with remarkable uni 

 formity. Thus far only two sub- 

 generic names have been proposed 

 for subordinate groups within the 

 genus Baiomys, erected by True 

 in 1894 * for the tiny species P. 

 taylori, and Megadontomys, pro 

 posed by Merriam in 1898 f for 

 the largest species of the genus 

 P. thomasi. Both of these are well 

 characterized, but represent abej.*- 

 rant types rather than assem 

 blages of species. Baiomys con 

 tains only two well-marked spe 

 cies (each possibly divisible into 



i -i >. T -n/r ^ FIG. 1. A. Upper molars of Peromuscus 



several subspecies) and Megadon- ( Peromyscu v S ) felipensis . B . u PP er mo- 



tomys is represented by Only the \*.vsofPeromyscus(Haplomylomys)caU- 



type species and two closely re- fornicus ' (About> 



lated forms. All the other species are at present retained in 



*Proc. U. S. Nat. Mus., XVI, p. 758, 1894. 



fProc. Biol. Soc. Wash., XII, pp. 115-116, April 30, 1898; see also 

 Bangs, Bull. Mus. Comp. Zool., XXXIX, p. 27, 1902, where Megadontomys 

 is given generic rank. 



5 PBOC. BIOL. Soc. WASH. VOL. XVII, 1904 (53) 





