344 
COMPARATIVE ZOOLOGY. 
Subclass III.— Monodelphia or Placental Mammals, 
Ill 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 
and Ant-eaters are cov- 
Fig. 333.—Skull of the Great Ant-eater ( Myrme - 
cophaga jubata) : 15, nasal ; 11, frontal; 7, pa- 0j*0d with C0arS6 hair * 
rietal; 3, superoccipital; 2, occipital condyles; # ? 
28, tympanic; 73, lachrymal ; 32, lower mandi- the Armadillos and Pan- 
ble. Teeth wanting. ,. . . » 
goiins, 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 no incisors. The Sloths are arboreal; the 
Fig. 334.— Armadillo ( Dasypus). 
