ELIOMYS 555 



median spine, the slightly curved hamular in contact with audi- 

 tory bulla at tip. External pterygoid plate evident though small, 

 foruiing a distinct pterygoid fossa. Mandible slender, the ramus 

 curved in front of tooth-row, coronoid process long, sloping 

 gradually backward, its point considerably above level of 

 condyle ; angular process well developed, short and deep, the 

 middle of lower border with abrupt angle, above which the bone 

 is perforated by a conspicuous round vacuity about 1 • 5 mm. in 

 diameter. 



Teeth. — The teeth are moderately large relatively to size of 

 skull, the length of tooth-row contained about 2i times in palatal 

 length ; tooth-rows wider apart anteriorly than posteriorly, the 

 alveolar length equal to distance between anterior roots of 

 prejnolars. Incisors with no special peculiarities, the anterior 



Fig. 110. 

 Eliumijs quercinus. Cheek-teeth. X lu. 



sui'face smooth, light yellow, its diameter slightly less than 

 antero-posterior diameter, the discrepancy slightly greater in the 

 lower than in the upper teeth. Root of lower incisor extending 

 to that of m.^ ; dental foramen at level of alveolar line. Upper 

 cheek-teeth with crowns deeply concave, the inner and outer 

 borders noticeably elevated. Molars sub-equal, the second 

 slightly the lai'gest, the crowns squarish, slightly wider than 

 long, the inner border a little rounded, the posterior border of 

 m^ shortened ; inner border of crown with a robust, moderately 

 high cusp, the most elevated portion of which is in front of 

 middle, its base occupying nearly entire inner border, but in 

 some specimens succeeded by a minute posterointernal cusp 

 early disappearing with wear ; outer border with two moderately 

 large subterete cusps, the second not so large as first (the 

 discrepancy greater in «t^ than in the other teeth) and two or 



