R. S. Lull — Primitive Pecora in Yale Museum. 117 



ridges. P 4 a unique tooth, triangular in section, with 

 outer crescent not fully evolved, flanked by three faint 

 ridges on its outer face ; postero-internal cingulum form- 

 ing a sharp, straight ridge abutting against the well devel- 

 oped deuterocone but distinct therefrom in the unworn 

 tooth. Measurements : 



mm. 



Length P 2 to M 3 27 



Length, M 1 to M 3 17 



Length, M s 7 



Width, M 3 , at base of ant. crescent 5 



Lower dentition. — P 3 -M 3 a continuous series. Prob- 

 ably slight diastema separating P 2 and P 3 , but condition 

 of specimen renders this uncertain. Molars simple, with 



Fig. 1 



Qk 



Fig. 1. — Nanotragulus loomisi, gen. et sp. now Holotype. A, left upper 

 dentition. B, right lower dentition. X a little more than 3. 



slightly developed cingula on anterior face. No acces- 

 sory pillars. Posterior column of M 3 as in Hypertrag- 

 ulus, with outer and inner lobes opposite and not 

 separated posteriorly by a cleft as in Leptomeryx. P 2 a 

 simple, compressed cone, two-rooted, slightly recurved. 

 P 3 high-crowned, but not so much so as in Hypertragulus, 

 hardly rising above P 4 , with a main anterior cusp and 

 rather prominent heel. P 4 the most complex, laterally 

 compressed, high protoconid, and pronounced heel. 

 Antero-internal cusp well developed. Protoconid flanked 

 on inner side by a second cone which is confluent with it, 



