Article VII.— THE EXTINCT CAMELID^ OF NORTH 

 AMERICA AND SOME ASSOCIATED FORMS. 



By J. L. WORTMAN, MJ). 

 Plate XI, and Twenty-three Text Cuts. 



Among the living selenodont Artiodactyla the Camels and 

 Llamas of the Old and New World represent a very aberrant 

 group. Even if one were not familiar with the wonderful record 

 of their past history as revealed in the Tertiary deposits of this 

 country he would be quite justified, from the number of anatom- 

 ical peculiarities which they exhibit, in placing their origin far 

 back in the Tertiary, at a time when the primitive divergence of 

 the various lines of the Selenodonts was taking place. 



The evidence is not yet sufficiently complete to trace the 

 phylum with absolute certainty below the upper Eocone or Uinta 

 stage, but from this point on to the present time there is very 

 Httle to be desired, in the way of intermediate species, to form a 

 compact and closely connected series, reaching to the modern 

 types. 



More or less elaborate studies of this group have been made 

 by Cope' and Scott,'"' to whom we are especially indebted for 

 much knowledge concerning the extinct forms, and while it would 

 be difficult to add anything to their statements from the speci- 

 mens known to them, yet the acquisition of a large amount of 

 new material bearing upon this subject by the various Museum 

 expeditions within the past few years has rendered it especially 

 desirable to review the whole subject, with a view to defining, if 

 possible, the exact limits of the various genera and species of the 

 extinct North American representatives. The object of the 

 present paper, therefore, is: (i) A review of the genera and 

 species of the North American Tylopoda, with descriptions of 



' 'Phylogeny of the Camelidse,' Amer. Nat., 1886, p. 611. 



- 'On the Osteology of Poebrotherium,' Journ. of Morph., 1891. 'The Mammalia of the 

 Uinta Formation,' Trans. Amer. Phil. Soc, Aug. 20, 1889. 



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