VOL IX, pp. 117-128 JULY 2, 1894 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



ABSTRACT OF A STUDY OF THE AMERICAN WOOD 



RATS, WITH DESCRIPTIONS OF FOURTEEN 



NEW SPECIES AND SUBSPECIES OF 



THE GENUS NEOTOMA. 



BY DR. C. HART MERRIAM. 



The following brief abstract of a study of the North Ameri 

 can Wood Rats and Desert Rats, with descriptions of a dozen 

 new forms from Mexico and the western United States, based on 

 the rich collections of the United States Department of Agricul 

 ture, is here published in advance of a more formal paper on the 

 group. The genus Neotoma is here restricted to the species in 

 which the crown of the last lower molar is made up of two trans 

 verse loops; the species having the crown of this tooth shaped 

 like the letter S are transferred to the genus Ptyssophorus of 

 Ameghiuo, previously known from a single fossil species from 

 South America. As thus restricted, the genus Neotoma is divided 

 into two subgenera, Neotoma proper and Teonoma, which are 

 complementary in their geographic distribution, Neotoma proper 

 being Sonoran or Austral, while Teonoma is Boreal. It is con 

 venient to subdivide the former into four minor groups, none of 

 which is worthy of the distinction of subgeneric rank. These 

 groups may be designated, from a typical species in each, as fol 

 lows : (1) the leucodon group ; (2) the mexicana group ; (3) the 

 desertorum group, and (4) the arizonae group. 



Subgenus NEOTOMA Ord, 1825. 



Type, Neotoma flondana Ord, from Florida. 



Tail commonly round, scant-haired and tapering, but in one species mod 

 erately bushy ; hind feet small or moderate. 



