GLis 575 



E. querchms except that nasals are abruptly bent downward at 

 tip and venti'al border of auditory bulla does not descend evidently 

 below level of pterygoids. Surface of brain-case smooth, its 

 general outline between squarish and ovate when viewed from 

 above, the parietals bent downward along outer edge as in 

 Eliomys ; interparietal lozenge-shaped, its antero-posterior diameter 

 about half transverse diameter, rarely approaching ligulate. 

 Auditory bulla much less inHated than in Eliomys, particularly 

 in its posterior portion, which is not visible when skull is viewed 

 from above, and is not closely appi'essed to paroccipital process, 

 the general outline of bulla from side sub-circular, the anterior 

 border extending about to posterior border of glenoid surface ; 

 width of basioccipital at basal suture considerably more than 

 half distance from suture to foramen magnum instead of barely 

 one-third this distance as in Eliomys. Interorbital region with 

 well developed lateral ridges, low in the young, becoming higher 

 in adults and finally uniting to form a median crest. Zygomata 

 more abruptly spreading than in Eliomys, their median portion 

 often parallel, the middle of each jugal angularly expanded 

 upward, the zygomatic process of squamosal with abrupt posterior 

 concavity when viewed from above. Posterior termination of 

 nasals pointed or truncate, about at level of nasal branch of 

 premaxilla and front of lachrymal. Incisive foramina as in 

 Eliomys but shorter, the greatest length about one-third that of 

 diastema. Palate and mesopterygoid space essentially as in 

 Eliomys, but hamular not in contact with bulla, and ectopterygoid 

 reduced to a low ridge. Mandible much more robust than that 

 of Eliomys, especially in its anterior portion ; coronoid process 

 nK)re robust, strongly curved, its point high above level of 

 condyle ; angular portion entire. 



Teeth. — Incisors as in Eliomys but more robust. Upper 

 cheek-teeth relatively larger than in Eliomys, their outlines 

 s(][uarish, the first and second molars sub-equal, the third smaller, 

 narrowed posteriorly ; premolar slightly less than half as large 

 as first molar. Crowns low and nearly flat, but inner and outer 

 border slightly raised. The crown of each tooth is crossed by 

 four complete ridges, the postei'ior of which is least developed ; 

 between these three incomplete ridges extend inward to or a 

 little beyond middle, the second reaching outer side. These ridges 

 are best developed in m^ and ?h-, least developed in the premolar, in 

 which the first is often absent. Inner border of crown with four 

 low tubercles formed by the inner extremities of the four main 

 ridges, the fourth smaller than any of the others. Outer margin 

 of m^ and m- with five similar but smaller tubercles formed by 

 the outer extremities of the four main ridges and the middle 

 incomplete ridge. In the premolar the incomplete ridge does 

 not extend to outer margin of crown, while in m^ the structure 

 of all the ridges becomes indefinite near periphery of crown. 

 Lower molars essentially like the maxillary teeth, but with 



