84 



MICROTIN^ 



inflated ; their external apertures are very small and their walls 

 are strengthened by a stout and wide meshwork of bony trabe- 



FiG. 53. — Elldbius tancrei Blasius. 



Lateral and ventral views of a skull dissected to show the alveolar courses 

 of the teeth (enlarged); a. marks the position of the growing base of 

 the upper incisor and in the ventral view points to the maxillary 

 fenestra. 



culiE ; the stapedial artery is enclosed throughout in a bony tube. 

 The mandible has lofty recurved coronoid processes, and the 

 angular processes are reduced in each ramus to a mere ridge 





