BVOTOMYS 



649 



of middle, and posfcorbital processes tending to spread laterally 

 along posterior border of orbit as in Microtus rather than to 

 assume the bluntly peg-like form characteristic of Evotomys. 

 Brain-case rather long, the occipital region extended backward 

 by the unusually broad interparietal. Basioccipital narrow as 

 in E. glareolus, not widened as in the large E. caesarius, its width 



FIG. 127. 

 Evotomys vufocanus. Nat. size. 



along anterior suture equal to about one-third length from suture 

 to foramen magnum. Auditory bulla; rather large, slightly more 

 narrowed antero-internally than in E. glareolus. Palate rather 

 narrow but not peculiar in form. Anteorbital foramina relatively 

 smaller (narrower) than in any of the other European members 

 of the genus. Mandible without special peculiarities. 



Teeth, — Relatively to size of skull the teeth are larger and 

 heavier than in the other European members 

 of the genus, a peculiarity which is to the 

 eye exaggerated by the contrast with narrow 

 palate. The enamel pattern of the molars 

 agrees with that of Evotomys glareolus in 

 number and arrangement of the elements ; 

 m 3 normally with only two re-entrant angles 

 on inner side (see Table, p. 631), and with 

 first outer re-entrant angle tending to be 

 deep, as in E. rutilus. It is peculiar, how- 

 ever, in a certain tendency to acuteness of 

 the salient angles, a character especially 

 noticeable in not fully adult individuals, and 

 in the constancy with the triangles of all 

 three upper molars and of m 1 become completely closed. 

 Anterior loop of m 1 with inner reentrant angle relatively deeper 



Evotomys mfocanus. 

 Enamel pattern, x 5. 



