74 SCOTT. 



EXPLANATION OF PLATE I. 



Fig. i. Pcebrotherium Wihoni. Skull of a young animal, side viewXf. Mu- 

 seum of Comparative Zoology. 



Fig. 2. Pcebrotherium Wihoni. The same, top view X f • 



Fig. 3. Pcebrotherium Wilsoni. The same, base view X f • 

 f. ov. foramen ovale ; f. opt. optic foramen ; f.l.a. foramen lacerum anterius and 

 foramen rotundum. 



par. oc. paroccipital process; p. sp. presphenoid; b. sp. basisphenoid; f.l.p. 

 foramen lacerum posterius; pal. palatines. 



Fig. 4. Procamelus occidentalis. Skull, top view X 3<3> after Cope. 



Fig. 5. Procamelus occidentalis. Skull, base view X x /i, after Cope. 



Fig. 6. Procamelus angustidens. Skull, side viewX^. Cope collection, p-gl. 

 for. postglenoid foramen; po.ty. post-tympanic process of squamosal; p.oc. par- 

 occipital process. 



Fig. 7. Pcebrotherium labiatum. Tympanic region, natural size. con. occipital 

 condyle; par. paroccipital process; ty. tympanic bulla; m. a. e. external auditory 

 meatus. 



Fig. 8. Posbrotherium Wilsoni. Superior molar series, crown view, natural size. 



Fig. 9. Pcebrotherium Wilsoni, inferior molar series, crown view, natural size. 



