PLATE T 



All similar views are made on the same scale, irrespective of actual 

 size, and as nearly as possible in exactly similar positions so as to facilitate 

 direct comparison. The lettering is the same for all the skulls, and is the 

 initial letter or letters of the bones referred to : N, nasal ; Px, pre maxillar}' ; 

 Mx, maxillar\^; M, molar; Fr, frontal; Sq, squamosal; Pa, parietal; Ip, in- 

 ter-parietal; Oc, occipital. 



Fig. 1. Muskrat; natural size. Fig. 2. Beaver; reduced one-half. Fig. 3. 

 Common Brown Rat; enlarged one-half. Fig. 4. Gjey Squirrel; natu- 

 ral size. Fig. 5. Chipmunk ; natural size. 



Fig. 6. Hinder aspect of tibia and fibula of Pocket-Gogher, Fig. 7. Hinder 

 aspect of tibia and fibula of Beaver; reduced one-half. Fig. 8. Hinder 

 aspect of tibia and fibula of Prairie Dog. 



