262 PROCEEDINGS OF THE ACADEMY OF [1894. 



DESCRIPTIONS OF EIGHT NEW POCKET MICE (GENUS PEROGNATHUS). 

 BY DR. C. HART MERRIAM. 



Among the Pocket Mice belonging to the collection of the U. S. 

 Department of Agriculture, now numbering upwards of 1,400 speci- 

 mens, are several that have not been named. Through the courtesy 

 of the Assistant Secretary of Agriculture, Dr. Chas. W. Dabney, 

 Jr., I am enabled to publish the accompanying descriptions and 

 illustrations in advance of their publication by the Department. 



Respecting the eight forms here proposed, it may be stated that 

 P. baileyi is a type very different from any heretofore described. It 

 is a large animal with a peculiar skull, which suggests affinities with 

 P. jmradoxiis on one hand, and with P. fonnosus on the other, 

 though much nearer the latter than the former. P. columbianus is 

 a peculiar local form of the oUvaceas group. P. nevadensis, pana- 

 viiiithius, and inexlcaiiiis are small forms with much swollen mastoids, 

 belonging to the favus-Ioiif/hneiiibri^ group. P. nehoni, stepheusi, 

 and canesGens belong to the penicillatus group of the subgenus 

 Chijetodipus. 



Tlie large series of specimens from Mexico, in the Department 

 collection, carry the range of the genus southward over Sonora in the 

 west, and in the east over the states of Chihuahua, Coahuila, 

 Tamaulipas, Durango, San Luis Potosi, Zacatecas, and the Valley 

 of jNIexico. 



Perognathus baileyi sp. nov. (Fig. 1). 



Type from Magdalena, Sonora, Mexico. No. }^-?ll, 9 , ad., U. 8. 

 Nat. Museum, Department of Agriculture Collection. Collected 

 November 3, 1889, by Vernon Bailey. (Original number 633.) 



ilfea*-M/r;»(^'>//.s- (taken in flesh}. — Type: Total length, 210 mm; tail 

 vertebne, 122; hind foot, 27. Ear from anterior base, 11 (in dry 

 skin). Average measurements of 8 specimens from type locality : 

 Total length, 215; tail vertebrie, 120; hind foot, 27. 



General characters. — Size large ; tail long and moderately crested 



