Dorsal ami ventral view of same skull in each ease; 

 very close to natural size. 



Fiji. 1. Thomomys rlirysaitnliis, type; male, no. 10017; Ehrenberg, 

 Arizona; March 'J7. 1910. Note small size, short heavy rostrum, wide 

 interorbital constriction, narrow and rounded zygomatic arches, evenly 

 terminating nasals and premaxillary tongues posteriorly, and rounded 

 auditory bullae. 



Fig. 2. Thomomys perpallidus, topotype; male, no. 16500; Palm 

 Springs, California; February 10, 1912. 



Pig. .'!. Thomomys albatUS, type; male, no. 10018; Colorado River bot- 

 tom near Pilot Knob, California; May 7, 1910. Note large size, widely 

 spreading zygomatic arches (hiring anteriorly, broad nasals and premaxillary 



tongues, deep baying in anterior zygomatic root, and depressed auditory 

 bullae. 



Pig. 4. Thomomys perpes, probably not typical; male, no. 4063; Victor- 

 ville, Mohave Desert, California; December 27, 1906. 



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