10 



living Edentates are the Armadillos, Ant-eaters, and 

 Sloths, species of which are found in South America, 

 Southern Asia, and Africa. 



Among Monodelphians, the Edentates recall not 

 only implacental mammals, but Sauropsidans, at the 

 same time that they manifest relationships to the Non- 

 Deciduates, Zonarians, and Discoidans. Lying at the 

 root of the Discoida, they sum up many preceding 

 forms, but are apparently reversions rather than gen- 

 eralized Monodelphians. 



The Cetacea, or Whales, may be regarded as the 

 opposite members of the lower pair of branches of 

 Monodelphians. In external form they represent the 

 Fishes, as the (rli/pfodou among p]dentates reminds us 

 of the Tortoises. 



The next pair of branches are the Non-Deciduates 

 and Zonarians. The former includes Siren ia, Ungu- 

 Inta, and Toxodontia. 



Sirenia (Manatees and Dugongs) descends to ap- 

 proximate the whales. The Toxodonts are an extinct 

 Quaternary group approaching both the Sloths and 

 the Bears, and also bearing relations to members of 

 the Discoida. They mu-^t I)e regarded as an ascending 

 group, in the same manner a>< Sirenia is a descending 

 one. 



The Ungulates, or hoofed animals, form the main 

 central stem of the Non-Decidua, and include some of 

 the most important of our domestic animals, as the 

 hog, the cow, and the horse, with a large number of 

 extremely interesting familie-^, both living and extinct. 

 The ungulates appeared in the Eocene Tertiary with 

 members closely related to the Zonarians as well as to 



