248 On the Extinct Dogs of North America. [ March, | 
epitomize the history of the evolution of the dentition of the 
order of Carnivora. This I stated as follows, at a meeting of the 
Philadelphia Academy of Feb. 16, 1875: “The important 
change [in the Carnivora] which is clearly indicated, is the pro- 
gressive extinction of the genera with numerous sectorial teeth, 
accompanying the increasing specialization of those which 
remain. In other words the numerous types of digitigrade Car- 
nivora which have survived, are those developing one sectorial 
tooth (whose earliest representative is Didymictis). The increased 
perfection of the sectorial has been associated with a reduction in 
the number of the other molars, first posterior, then anterior to 
it, which reduction has been accompanied by an increased rela- : 
tive size of the sectorial.’”’ These views were extended in a paper | 
on “ The Origin of the Specialized Teeth of the Carnivora,’ it 
the American NATURALIST for March, 1879. Ina paper p a 
lished in the Proceedings of the Zodlogical Society of London 
August, 1880, Professor Huxley comes to the same conclusion 1 
that I have stated in the above papers, in apparent ignorance of ' 
their prior publication. 
As regards the origin of the Canidæ, it is doubtless to be 
found among the forms of the Creodonta? The Creodonta a 
flesh-eaters of various degrees of power, without scapholunat 
bone; with well defined canine teeth; with a low type of brat, 
and generally imperfect ankle-joint. They stand in nearest ce 
tion to the Insectivora, but have points of resemblance 0 
the Marsupialia. I originally included them as a sub-divisit 
of the Insectivora,? but subsequently placed them with e 
- Insectivora and several other sub-orders in a comprehensive onde 
which I termed the Bunotheria‘ This view of the origin of # 
Carnivora was subsequently reaffirmed by Huxley in his P 
of 1880, above cited. He reproduces all my evidence, and i 
the Canidz among the Creodonta® They are the only ™ 3 
1 Proceedings; p 22. 4 
32See Report U. S. Geol. Survey W. of rooth mer. G. M. Wheeler, 1877) 
282, 
3 Proceedings Academy Philada., 1875, Nov., p. 447- 
t See Report Capt. Wheeler, 1877, 1v, 
P. 95. : 
$ On the genera of the Creodonta, Proceed. Amer. Philcs. Scc. 1880, p. 5 
