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 Fayam 
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. 
| 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, Bul. Amer. Mus. Nat. Hist., vol. 27, p. 
273-285, 1910. 
