COMPARATIVE ZOOLOGY. 



SUBCLASS III. Monodelphia or Placental Mammals. 

 In these Mammals the young are connected with the 

 mother by means of a vascular structure, the placenta, by 

 which they are nourished. They are born in a relatively 

 perfect condition. 



3. Edentata. This strange order contains very diverse 

 forms, as the leaf-eating Sloths and the insectivorous Ant- 

 eaters and Armadillos of South America, and the Pango- 

 lin and Orycteropus of the Old World. The gigantic fos- 



sils, Megatherium and 

 Glyptodon, belong to 

 this group. The Sloths 



P,a.333._Sknll of the Great Ait-eater (Myrme- and Ant-CatCl'S are COV- 



r.ophaga jubata) : 15, uasal ; 11, frontal ; 1, pa- e red With COai'SC hair: 

 rietal; 3, superoccipital ; 2, occipital condyles; 



28, tympanic; 73, lachrymal ; 32, lower maudi- the Armadillos and 1 ail- 



golins, with an armor of 



plates or scales. The Ant-eaters and Pangolins are strict- 

 ly edentate, or toothless; the rest have molars, wanting, 

 however, enamel and roots. In general, it may be said 

 that the order includes all quadrupeds having separate, 

 clawed toes and uo incisors. The Sloths are arboreal ; the 



Fi. 334 Arm 



