200 MEMOIRS OF THE CARNEGIE MUSEUM. 
associated with a skull of a Chalicothere so located as to leave no alternative to 
the discoverer but to conclude that the skull and the remainder of the skeleton 
belonged to each other and represented but one individual. 
The discovery that the heads and the feet, so long sundered in the classificatory 
systems which were in vogue, really belonged together, necessarily raised a number 
of interesting questions as to the true systematic position of the animals to which 
they belonged. The Chalicotheres, known by their dentition only, had long been 
recognized as Ungulates, and as pertaining to the suborder Perissodactyla; but, 
when it became known that the edentate-like feet must be recognized as forming 
a part of the structure of the animals, systematists were led to inquire whether 
perhaps they had not been mistaken in referring Chalicotherium and its allies to 
the Perissodactyla. Professor E. D. Cope very shortly after the announcement 
by Filhol and Depéret of their conclusions came forward with the proposition to 
erect a new order for their reception, to which he gave the name Ancylopoda. 
Professor H. F. Osborn in a paper published in the American Naturalist, 
February, 1893, with apparent hesitation, accepted Professor Cope’s view, but 
characterizes it as “‘radical,’’ and, evidently still impressed by the affinities shown 
by these animals to the Perissodactyla, save as they are possessed of apparently 
unguiculate phalanges, states that the purpose of his paper is ‘‘not to express a 
final opinion, but to suggest inquiry,” and leaves the reader to infer that upon the 
whole the relationship of this group of animals to the Ungulata, and especially 
the Perissodactyla, continued to profoundly impress him. Subsequently Professor 
Osborn in his monograph upon the ‘‘ Extinct Rhinoceroses”’ (1898) suggested the 
subdivision of the suborder Perissodactyla into five superfamilies, the fifth of which 
he tentatively named the “Chalicotherodea.”’ 
The material recovered by the various expeditions of the Carnegie Museum, 
by means of which we have been able to reconstruct the entire skeleton of one 
species of the genus Moropus, led Mr. Peterson in the paper which he read before 
the Zodlogical Congress held in Boston in 1907, to advocate with firmness the 
view that “‘ Moropus is, excepting its unguiculate feet, essentially perissodactyl in 
structure.”’ 
The authors of this paper, in the fuller light possessed by them, have resolved 
accordingly not to accept the more radical view of Professor Cope, and prefer to 
adopt what they believe to be the preferable course, holding with Zittel and others 
the view that the Chalicotheres are at most entitled to be regarded as representing 
a superfamily of the Perissodactyla, to which the name Chalicotheroidea, first 
proposed by Dr. Gill, must apply. So far as is now apparent, with all the literature 
