ANTELIOMYS 



295 



though slightly dorsal to the ventral surface of the basisphenoid. 

 Auditory bullae simple, without spongy tissue internally ; stapedial 

 artery not enclosed in a bony tube. 



Mandible without special peculiarities; m^ displaced 

 lingually by the shaft of the lower incisor. 



Dentition. Incisors normal ; upper incisors strongly curved, 

 slightly " opi.sthodont." Cheek-teeth hypsodont and rootless, 

 the capsule of jw^ noticeably obstructing the mouth of the sphen- 

 orbital fissure ; enamel about equally thick on convex and concave 

 sides of prisms ; dentinal spaces of mandibular molars and usually 

 of maxillary molars more or less confluent ; re-entrant folds with 

 cement. Enamel pattern (Figs. 88, 89) ; m^ and m^ nearly 

 normal, the triangles following the anterior loop in each tooth 

 sometimes substantially closed, often more or less confluent; 

 a vestigial trace of the fourth inner angle in m^ and of the corre- 

 sponding third inner angle in m^ often present ; wr very complex 



Fio. 89. — Cheek-teeth of Anteliomys wardi Thomas. 

 a. Right upper, h. left lower molars. 



and peculiar, usually with four or five salient angles on the outer 

 side and five or six salient angles on the inner side ; in one form 

 [A. cJiinensis tarquinius) the number of salient angles is usually 

 reduced to four on each side by suppression of some of the 

 posterior elements of the tooth; in normal forms the anterior 

 loop is followed by seven or eight alternating triangles, the first 

 outer infold is shallow leaving the first triangle confluent with the 

 anterior loop as in Alticola and some other genera, the second 

 outer fold is deep substantially closing off the second triangle 

 (second inner angle), while the third and fourth outer folds are 

 very shallow leaving all parts of the tooth behind the second 

 triangle more or less confluent with each other. In A. c. tar- 

 quinius the outer folds of m^ are deeper so that four or five of the 

 triangular dentinal spaces, including the first outer triangle, 

 '' behind the anterior loop are substantially closed. The mandibular 

 molars do not differ in any essential respect from those of 

 Eothenomys. 



Remarks. — Anteliomys differs from its closest ally Eothenomys, 

 chiefly by the tendency to approximation in the interorbital 



