Ill 



ciently resembles the tooth of Fig. 27, Plate VI, originally referred to P. 

 delicatior, to pertain to the same species, though it is slightly larger. 



The other specimen, apparently from the same individual, consists of a pair 

 of upper molars represented in Figs. 17, 18, Plate XXVII, magnified three 

 diameters. They have nearly the form and construction of those of the 

 Sciu rides. 



The fore and aft diameter of the lower molar is 1.8 lines.. The fore and 

 aft diameter of the upper molars is 1.8 lines, and the transverse diameter is 

 2 lines. 



Paeamys delicatissimus. 



A third and still smaller species of Paramys is indicated by a specimen 

 consisting of the greater portion of the right ramus of a lower jaw contain- 

 ing all the molars, and a second specimen consisting of a small fragment of 

 another lower jaw containing the second molar. The first specimen of the 

 natural size is represented in Fig. 28, Plate VI. A view of the triturating 

 surfaces of the molars, magnified three diameters, is given in Fig. 29. The 

 molar series measures ^ an inch in length, and the animal was about the size 

 of the common gray squirrel. 



Comparative measurements are as follows : 



Lcugtb of lower molar series 



Leugtb of hiatus in advauce of lower molar series 



Depth of jaw below the second molar 



Fore and aft diameter of incisor 1 



Transverse diameter of iucisor s 



Fore and aft diameter of second molar 



Transverse diameter of second molar 



P. rielica- 

 tus. 



Line*. 



9 



34 



G 



H 



i* 



•>i 



14 



F. delica- 

 tior. 



Lines 

 74 



H 

 H 



1*. delica- 



tissimus. 



Lines. 

 6 

 3 

 1 



14 

 11 



n 



MYSOPS. 



Mysops minimus. 



A small rodent, intermediate in size to the common mouse and the brown 

 rat, is indicated by a specimen discovered by Dr. Carter at Grizzly Buttes 

 and sent to the author last summer. The specimen consists of the median 

 portion of the right ramus of a lower jaw containing the last two molars, the 



