PLATE LIII.' 



Fig. 1. — Left mandibular ramus of PuVaeos;/o^w valUdens. Oue-half natural size ; profile. From Mam- 

 moth Buttes, Wyo. Page 699. 



Fig. 2. — Hyrachyus eximius. Mandibular right ramus of individual figured in Plate LVIIa, figs. 6-7 i 

 2a, same, from above. Page 662. 



