168 
JOUBNAL OF MAMMALOGY 
some Microtus, hut much to my surprise on visiting the traps next morn- 
ing one held a specimen of P. albipes. During the next few days I took 
two more of these rare mice, as well as specimens of Microtus oregonuSj 
Per omy sens m. ruhidus, and Sorex vagrans, all within twenty-five yards 
of each other. Along a small stream nearby I took one each of Spilo^ 
gale latifrons and Neotoma c. fusca, in the only steel trap I had. As 
the Spilogale was an old male I have often wondered how many albipes 
he had collected. 
From the foregoing it would appear that Phenacomys albipes is far 
from common in the state of Oregon. We know practically nothing 
of its habits, except that it feeds on the ground in dense forested areas. 
All those I have taken were trapped with oatmeal for bait. 
A NEW GENUS OF RODENTS FROM THE MIDDLE EOCENE 
By W. D. Matthew 
In the collections obtained by the American Museum expeditions 
of 1903-06 in the Bridger Basin, Wyoming, were several skeletons of 
rodents. Some, but not all, of these were prepared and described in 
1909, in an article by the present writer. During this winter a num- 
ber of specimens in the Bridger collection have been prepared for study. 
Among them is a very well preserved rodent skeleton, consisting of the 
skull, jaws, fore and hind limbs and feet, pelvis and some vertebrae. It 
appears to belong to “ Paramys” delicatissimus Leidy, 1871, but is 
clearly not congeneric with the type of Paramys, P. delicatus. The 
following generic diagnosis may serve to indicate the principal differ- 
ences observed : 
Reithroparamys gen. nov. 
Type, Paramys delicatissimus Leidy, from the Bridger formation, Middle 
Eocene of Wyoming. 
Genotype, Am. Mus. No. 12561, skull, jaws, and most of skeleton. 
Incisors narrow, deep, laterally compressed, the upper pair slightly grooved 
on the anterior face. Cheek teeth sciuroid, much as in Paramys, and not dis- 
tinguished by any clearly generic differences. Skull with two parallel raised 
postorbital crests and a lyrate area behind, instead of the single median crest of 
Paramys. Tympanic bulla of medium size, ossified except towards the posterior 
margin; no bony meatus. The bulla in Paramys is not ossified, nor is it so in 
any of the nearly related genera or subgenera from the Middle and Upper Eocene, 
so far as is known. Limbs comparatively long and slender, the hind foot bones 
long and slim, the fore foot bones relatively small. First metatarsal long but 
slender, fourth heavier than third, fifth much shorter but comparatively stout. 
