850 The American Naturalist. [October, 
equally learned should follow in his steps is asingular psycho- 
logical curiosity. 
I need scarely add that the law of correlation applied by 
Cuvier to the structures of ruminants entirely fails in the case 
of many extinct mammals discovered since Cuvier’s days. 
Zadig would have been completely nonplussed if he could 
have seen the imprint of an Agriocherid, a Uintatherid or a 
Menodontid. 
I have given this quotation for two reasons : first, to indicate 
how the increase of our knoweldge has revolutionized old 
conceptions; and second, to show how even the ablest of men 
may stumble. 
Cope has been much criticised for the mistakes and false 
generalizations he made. Unquestionably he did make many. 
But error seems to be inseparable from investigation, and if 
he made more than the other great masters he covered more 
ground and did more work. He was also, it must be admit- 
ted, more hasty than some others in that he availed himself 
of the more frequent means of publication he enjoyed. 
The great merit of Cope’s work on mammals is that he al- 
ways considered the old and new—the extinct and recent— 
forms together. He refused to be bound by consistency or by 
precedent, either set by himself or others. Fresh discoveries 
opened new vistas to him, and he modified his views from 
time to time and as often as he received new evidence. 
He introduced many new families in the system and sought 
to improve the system by the comparison of all the elements 
of the skeleton. He came to the conclusion that the affinities 
of the ungulate quadrupeds were best expressed by the manner 
of articulation of the bones of the carpus and tarsus; he asso- 
ciated those having the “carpal and usually tarsal bones 10 
linear series ” in a great order which he called Taxeopoda, and 
contrasted them with the Proboscidea and typical Ungulata, 
which he named anew Diplarthra. In the Taxeopoda he 
gathered many extinct families and associated with them 
forms of the existing fauna known as the Hyracoidea, Dau- 
bentonioidea, Quadrumana and Anthropomorpha. I cannot 
altogether assent to this collocation inasmuch as I think the 
