1898.] Osboni, Evolution of tlie A Diblypoda. Parti. 217 



foramen is not even grooved. In No. 2870 the tibiale facet is 

 irregular, and a groove represents the astragalar foramen. In 

 C. testis, No. 258, the il)iale facet is irregular, the astragalar 

 foramen is wanting; in No. 2869 it is completely bridged over; in 

 No. 4300 (Cope's cotype) it is partly bridged over. 



2. In the relative constancy of the tibiale facet and of the astra- 

 galar foranien or groove, the pes of Uiutiitherium mi7'abile is there- 

 fore more primitive than that of Corypliodoii. 



Conclusion of Part I. 



The phylogenetic conclusions drawn from this analysis of the 

 Taligrada and Pantodonta will be more fully discussed at the close 

 of Part II of this paper, which will treat of the Dinocerata. 



The two main results thus far brought out are these: First, the 

 demonstration of a number of separate phyletic lines of Coryph- 

 odons; these lines probably represent the local differentiations 

 of the Coryphodon type in adaptation to different feeding ranges, 

 that is, swamp, plain, and upland. The second result is, that 

 certain Coryphodons approach the Dinocerata in some structures 

 as closely as they depart widely from them in others; for example, 

 C. anitatiis resembles Uintathcriuin in canine type, but differs from 

 it in skull type ; C. testis approaches Uintatheriinn in the upper 

 posterior portion of the skull, but differs from it widely in the 

 anterior portion of the skull, and in the structure of the canine 

 teeth ; C. radians shows the assumption of the incisiform shape 

 by the lower canines, so distinctive of UintatJieriuni. But no 

 Coryphodon is fully known which fills all the conditions of an 

 ancestor of Uintatherium. Until the skull of Bathyopsis is known 

 the transition between the above types will remain obscure. 



Bibliography — -Principal References. 



Cope, E. D. 1877. — Report upon the Extinct Vertebrata obtained in New 



Mexico by parties of the Expedition of 1874. U. S. Geol. 



Surv. west of looth Mer. Paleontology, Vol. IV, Part ii. 

 " 1884. — The Vertebrata of the Tertiary Formations of the West. 



U. S. Geol. Surv., Vol. Ill, Part i, 1884. 

 " 1884 (i). — The Amblypoda. American Naturalist, Nov. & Dec, 



1884, pp. irio-1121 and pp. 1192-1202. Jan., 1885, pp. 40-55. 



