KPIMYS 851 



a knife-like median occipital crest from interparietal to foramen 

 magnum. Interparietal large, its anterior border nearly straight, 

 though usually forming a median point, its posterior border 

 strongly convex. Occiput rather broad and low when viewed 

 from behind, but central portion of brain-case not rising con- 

 spicuously above it ; paroccipital processes slender and rather 

 long, extending beyond level of lower lip of foramen. Floor of 

 brain-case with no special features ; width of basioccipital along 

 anterior border scarcely half median length ; auditory bulla 

 moderately large, evenly inflated, its greatest diameter about 

 8 mm., meatus with thickened edges but not tubular. Inter- 

 orbital region contracted, its least breadth less than that of 

 rostrum over roots of incisors, its margin overhanging and 

 conspicuously beaded, the beads passing into lateral ridges of 

 brain-case behind a slight though evident angle at suture between 

 frontal and parietal. Zygoma rather slender, not expanded or 

 noticeably flattened, strongly bent downward, its lowest point 

 usually opposite m 3 ; anteriorly the arches are not abruptly 

 spreading, so that greatest zygomatic breadth is at glenoid level ; 

 plate forming outer border of anteorbital foramen well developed, 

 its anterior border vertical below, broadly rounded above. 

 Rostrum much deeper than broad but without special peculiarities 

 of form ; nasals truncate or bluntly pointed posteriorly, extend- 

 ing barely to lachrymal level, somewhat exceeded by nasal 

 branches of premaxillarieg. Incisive foramina parallel sided, 

 rather short and wide, their posterior border extending to level 

 of anterior root of Mi 1 , their anterior extremity falling short of 

 incisors by a distance equal to about one and one-half times the 

 width of the two foramina together. Palate extending notice- 

 ably behind level of m 3 . Mesopterygoid space slightly wider 

 posteriorly than anteriorly, truncate or double rounded in front, 

 the hamulars slightly turned outward, not in contact with 

 bull* ; ectopterygoid well developed, tilted noticeably upward 

 from within outward (skull viewed from below). Mandible 

 robust, with no special peculiarities ; coronoid process directed 

 strongly backward, slightly curved, its extremity rising notice- 

 ably above level of condyle. 



Teeth. — Teeth moderately large relatively to size of skull ; 

 upper molars with outer tubercles well developed, nearly as large 

 as those on inner side, the crescents rather flat but evident 

 and showing little tendency to distortion. Incisors strongly 

 compressed, without special peculiarities, the cutting surface of 

 upper tooth vertical, flat, its edges entire. First upper molar 

 5-rooted, the anterior root largest, strongly projecting forward 

 beyond base of crown, the median inner and median outer roots 

 smallest ; crown barely as long as that of w? and m 3 together, 

 its area about equal to that of the succeeding teeth ; anterior 

 border of crown smooth, with no trace of cingulum or minute 

 supplemental cusps; first lamina moderately and evenlv cresceutic, 



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