EXPLANATION OF PLATES 



Plate 1. Meniscotherium skull from the early Eocene of Wyoming 



Meniscotherium chamense Cope 



Skull (U.S.N.M. 22672), dorsal, lateral, and ventral views. Natural size. 

 New Fork member, Wasatch formation, Green River Basin. Wyo. 



Plate 2. Meniscotherium. skull from the early Eocene of Wyoming 



Meniscotherium robustum Thorpe 

 Skull (U.S.N.M. 18260), dorsal, lateral, and ventral views. 54X natural 

 size. La Barge, Knight member, Wasatch formation, Green River Basin, 

 Wyo. 



Plate 3. Meniscotherium skull from the early Eocene of Wyoming 



Figs. 1, 2. Meniscotherium chamense Cope. 1, Skull and mandible (U.S.N.M. 

 22918), lateral view. Natural size. 2, Basicranium (U.S.N.M. 22672), 

 ventral view. 2X natural size. New Fork member, Wasatch formation, 

 Green River Basin. Wyo. Explanation of abbreviations follows : 



a.c, alisphenoid canal. 



e.a.m., position of external auditory meatus. 



f.l.m., foramen lacerum medium. 



f .l.p.,foramen lacerum posterius. 



f.o., foramen ovale. 



fen. o., fenestra ovalis. 



fen. r., fenestra rotundum. 



gl., glenoid surface. 



h.f., hypoglossal foramen. 



p.gl.f., postglenoid foramen. 



p. gl.p., postglenoid process. 



p.p., paroccipital process. 



VII., aperture in facial canal for facial nerve. 



Plate 4. Meniscotherium type specimens 



Fig. 1. Meniscotherium robustum Thorpe. Skull and mandible (Y.P.M. 10101), 

 type specimen, lateral view. 23 X natural size. Left upper cheek teeth 

 (Y.P.M. 10101), type specimen, occlusal view. Natural size. Aspen, 

 Knight member, Wasatch formation, Green River Basin, Wyo. 



Fig. 2. Meniscotherium terraerubrae Cope. Maxilla and jaw portion (A.M. 

 4410), type specimen, occlusal view of upper teeth, lateral and occlusal 

 view of lower jaw fragment. Natural size. San Jose formation, San 

 Juan Basin, N. Mex. 



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