20 



REFERENCES TO THE PLATES. III. 



PLATE III. 



Fit's. 1 2. Cranium with both horn-cores of Boolhcrium cavifrons, one-fourth the diameter of nature. 

 Fig. 1. Superior view of the specimen. 

 Fig. 2. Posterior view of the specimen. 



PLATE IV. 



Fig. 1. Lateral view of the same specimen of the cranium of Bootherium cavifrons, represented in Plate 



III., also one-fourth the diameter of nature. 

 Fig. 2. Upper view of the cranium with both hom-corcs of Bootherium hovibifrons, one-third the diameter 



of nature. 



PLATE V. 



Figs. 1, 2. Views of the same specimen of Boothermm homhi/rons, represented in Fig. 2, Plate IV., also 



one-third the diameter of nature. 

 Fig. 1. Lateral view of the cranium. 

 Fig. 2. Posterior view of the cranium. 



PUBLISHED BY THE SMITHSONIAN INSTITUTION, 



WASHINGTON, D. C, 



DECEMBER, 1852. 



