10 Proceedings of the Biological Society of Washington. 



The following are the mammals whose capture seems worthy 



of note: 



Perognathus apache. 



A single specimen of this Pocket Mouse was taken attheSieber Ranch, 

 .Mesa County. No Pocket Mice of any species were taken at San Acacio, 

 though I saw a few holes on the prairie whieh I thought were, made by 

 these animals. 



Thomomys fossor. 



One taken in Culebra Canon at 8900 feet, and workings seen at various 



altitudes up to 10,700 feet, the highest altitude reached by me. 



Thomomys talpoides agrestis. 



Several Pocket Gophers were trapped near San Acacio. Unfortunately 

 most of these were young, the rest being adult females, no grown males 

 being taken. This rendered their identification somewhat difficult, but 

 Vernon Bailey of the Biological Survey, to whom they were submitted, 

 considers them T. agrestis, and they agree very well with topotypes of that 

 species in my collection. This extends the range of this species some 

 thirty-five miles southerly from the type locality, Medano Ranch, in north- 

 ern Costilla County, and is the more interesting because at Antonito, 

 about twenty-seven miles southwesterly, and on the west side of the bio 

 Grande River, Thomomys aureus pervagvs has been taken. Much yet 

 remains to be done to determine the ranges of the Pocket Gophers of the 

 San Luis Valley. 



My thanks are due to the Biological Survey and Mr. Bailey for examin- 

 ing the specimens. 



Microtus mordax. <* 



This Meadow Mouse was trapped at about 9100 feet in Culebra Canon. 



Neotoma mexicana fallax. 



This Wood Rat was taken at the Sieber Ranch, Mesa County; and in 

 the San Luis Hills, near San Acacio, Costilla County, this latter being the 

 first record of the species for any portion of the San Luis Valley. 



Neotoma desertorum. 



The capture of the Desert Wood Rat at Mack, Mesa County, extends 

 the range of this Lower Sonoran species into Colorado in an entirely new 

 region, the only previous record for the State being Rangely, on the lower 

 White River, where it was taken by Cary. I took several specimens in 

 sandstone ledges about a mile southwest of the railroad station at Mack, 

 w T here it seemed fairly common, judging from the nests seen. April 25th, 

 1912, young about a third grown were taken, and at about the same date 

 pregnant females w r ere captured. This would indicate that they begin to 

 breed very early in the spring, and that at least two litters are raised in 



