EXPLANATION OF PLATES. 



PLATE VII. 



Eocene Mammal, Dinoceras of Marsh. — Page 503. 



Figure 1. — Outline of skull and brain-cavity of Dinoceras mirab- 



ile Marsh : top view (one eighth natural size). 

 Figure 2. — Skull and lower jaw of Dinoceras (one eighth natural 



size). 

 Figure 3. — Left fore foot of Dinoceras (one fifth natural size). 

 Figure 4. — Left hind foot of Dinoceras (one fifth natural size). 



PLATE VIII. 



Eocene Mammals, Tillodontia of Marsh. — Page 503. 



Figure 1. — Outline of skull and brain-cavity of Tillotherium 

 fodiens Marsh : top view (one fourth natural size). 



Figure 2. — Skull and lower jaw of Tillotherium fodiens (one 

 fourth natural size) : a, upper incisor ; b, lower incisor ; c, condyle. 



Figure 3. — Last upper molar of Tillotherium latidens Marsh. 

 Natural size. 



Figure 4. — Lower molar of Anchippodus minor Marsh. Nat- 

 ural size. 



Figure 5. — Ungual phalanx of Tillotherium fodiens Marsh: 

 a, front view ; b, side view. Natural size. 



PLATE IX. 



Miocene Mammals, Brontotherium of Marsh. — Page 504. 



Figure 1. — Side view of skull of Brontotherium ingens Marsh 



(one twelfth natural size). 

 Figure 2. — Top view of skull (one twelfth natural size). 

 Figure 3. — Right fore foot (one sixth natural size). 

 Figure 4. — Right hind foot (one sixth natural size). 



PLATE X. 



Successive forms of the Horse type, from Marsh. — Page 507. 



Column 1. — Fore feet. 

 Column 2. — Hind feet. 



