CHAPTER IV 



UNGULATA 



The systematic arrangement of the South American 

 ungulates is of such a nature that scarcely two students of 

 these forms have agreed. I feel that the Pyrotheridae are 

 proboscideans as did Ameghino, but there my agreement 

 ends. The other varied groups I believe have a common 

 ancestry, their great divergencies being due to adaptations 

 to the greatly varied characters of the country they occu- 

 pied. In spite of the great variation they have certain 

 features in common so that I agree with those who have 

 developed the term Notungulata to include them all. 



From what source they originally came is not clear, but 

 it seems to me that these notungulates have more in com- 

 mon with what we know of the African fauna of the Fayum 

 than with any other fauna; so that my feeling would be 

 that these two faunas had a common ancestry at least, and 

 possibly the South American ungulates are derived from 

 the African. The lophiodont upper dentition, the bicres- 

 centric lower molars with a "pillar" in the posterior crescent, 

 the development of the tympanic bulla with the extension 

 of the inflated cavity up into the squamosal bone, the 

 development of the post-tympanic portion of the squa- 

 mosum, and the general arrangement of the basi-cranial 

 foramena indicate in my mind that these notungulates 

 have all risen from the same stock, and that that stock 

 had much in common with the hyracoids. 



I should therefore arrange the various groups as follows.* 



* The following references discuss in detail the arrangement of these forms. 

 Ameghino, 1906, Formations Sedimentaires, Anal. Museo Nac. de Buenos 

 Aires, ser. 3, t. 8, p. 287-498: Roth, Los Ungulados Sudamericanos, Anal. 

 Mus. La Plata, t. 5, 1903, p. 1-36: Scott, Princeton Patagonian Expeditions, 

 vol. 6, p. 287-299, 1912: Gregory, Bui. Amer. Mus. Nat. Hist., vol. 27, p. 

 273-285, 1910. 



