APPENDIX. 
Art. XIL—On the Structure and Affinities of the Brontotheride ; 
by O. C. MarsH. (With two plates.) 
the Dinocerata of the Eocene,+ which they seem to have replaced, 
they equalled them in size, and resembled them in seve 
Important features, notably in the structure of the feet, and in 
having the head armed with a pair of powerful horns. e 
general structure of the group, however, clearly indicates that 
sk do not belong in the order Dinocerata, but should be placed 
the Perissodactyls, in which they form a well-marked 
y- 
The 
out by the writer in describing Brontotherium gigas Marsh, the 
pee species, and others had been previously mentioned by Dr. 
eidy in his descriptions of Titanotherium Proutii.t The skull 
id Sa antag Symborodon and Miobasileus, recently indicated 
by Prof. Cope (Am. Nat., vii, p. 753), belong to this group. 
The former is generically identical with Brontotherium, the 
teputed absence of lower incisors being evidently due either 
to age, or to imperfect specimens. s is apparently the 
Same genus, and hence both names should be ed as 
Synonyms of Brontotherium. 
* This J. L. 3. Loe. cit., p. 117, Feb., 1873. 
s Journal, vol. v, __ —_ 187 oe P- a 
