1898.] Wortfuan, Extinct CaitielidcR of North America. 135 



the genus and species is known are, unfortunately, very fragmen- 

 tary, so that it is impossible to say much concerning it. It was 

 first found at the Silver Lake locality in southeastern Oregon, but 

 subsequently Cope identified remains referable to it from certain 

 localities in Mexico, showing that it was most widely distributed. 

 Two species have been described by Cope, E. conidcjis and E. 

 longirostris, but it is very doubtful indeed whether the material at 



Fig. 23. Crown view of upper teeth of A tichenia lama. 



present known warrants the recognition of more than a single 

 species. There are some trifling differences in the length of the 

 diastema of the lower jaw, it is true, but this is probably due to 

 individual variation. The size of the species about e(|uals that of 

 the Dromedary. 



The Evolution of the Camelid/E. 



We come next to consider the evolution of the Camelida^, and 

 although the principal facts of their development have been quite 

 fully set forth in the foregoing pages, yet it seems proper to 

 summarize them here. The earliest forms in which one can 

 detect true tylopodean peculiarities, as already pointed out, are 

 found in the upper Eocene or Uinta stage ; at the same time it is 

 quite certain that the phylum was detached from the main stem of 

 the Artiodactyla at a much earlier date. Both Cope and Scott 

 have expressed the opinion that the ancestry of the group is 

 traceable directly to the Wasatch genus Panfo/estes, and Scott 

 believes that the connection is established by the Bridger genus 

 Homacodon. Whether or not these opinions will bear the test of 

 future discovery time alone will reveal. At present I am of the 

 opinion that the osteology of these genera is too imperfectly 



