27 



both external and cranial, in this genus is strikingly great, 

 yet the transition between the extreme phases of the group 

 is so gradual that it is difficult to separate it into more than 

 two subgenera, and these are by no means trenchantly 

 limited. 



In Mr. True's List the genus Dipodomys contained I 

 species with I subspecies The group has since been 



Perognathus flavus Baird. Western Texas. 



Perognathus bimaculatus Merriam. Arizona. 



Perognathus longimeitibns (Coues). Southern California. 



Perognathus apache Merriam. Apache Co., Arizona. 



Perognathus inornatus Merriam. Fresno, Cal. 



Perognathus olivaceus Merriam. Kelton, Utah. 



Perognathus olivaceus amosnus Merriam. Nephi, Utah. 



Perognathus monticola Baird. Montana. 



Perognathus formosus Merriam. St. George, Utah. 



Perognathus intermedlus Merriam. Mud Spring, Arizona. 



Perognathus fallax Merriam. Southern California. 



Pei-ognathus obscurus Merriam. Grant Co., N. Mex. 



Perognathus spinatus Merriam. Lower Colorado River, Cal. 



Perognathus penicillatus Woodhouse. San Francisco Mountain, Arizona. 



Perognathus hispidus Baird. Charco Escondido, Mexico. 



Perognathus paradoxus Merriam. Trego Co., Kansas. 



Perognathus paradoxus spilotus Merriam. Cook Co., Texas. 



Perognathus californicus Merriam. Berkely, Cal. 



Perognathus armatus Merriam. Mount Diablo, Cal. 



Two other " undetermined species" were also mentioned, namely, Perog- 

 nathus lordi (Gray) and Perognathus mollipilosus Coues. There have since 

 been added : 



Perognathus fuliginosus Merriam, N. Am. Fauna, No. 3, p 74, Sept., 



1890. San Francisco Mountain, Arizona. 



Perognathus femoralis Allen, Bull. Am. Mus. Nat. Hist., III., p. 281, June, 



1891. San Diego Co., Cal. 



Perognathus merriam i Allen, ibid., IV., p. 45, March, 1892. Southeastern 

 Texas. 



Perognathus infraluteus Thomas, Larimer Co., Col. 



Perognathus lordi (Gray). British Columbia. Revived by Rhoads, Proc. 

 Acad. Nat. Sci. Phila., 1893, p. 405, Jan. 27, 1894. 



Perognathus copei Rhoads, ibid., p. 404. Staked Plains, Texas. 



Perognathus alticolus Rhoads,. ibid, p. 412. San Bernardino Mts., Cal. 



Perognathus lalirostris Rhoads, Am. Nat.,XXVIIL, Feb., 1894, p. 185. 

 "Rocky Mountains." 



