ORDER EDENTATA. 1 295 



to some of the Megatheriidce , in which there were a number of small 

 ossicles embedded in the dermis of the dorsal region. A similar con- 

 dition prevails in Carioderma, of the Loup-Fork beds of Texas. 



Family Myrmecophagid.e. — This family comprises the true 

 Ant-eaters of South America, represented by the genera Myrmeco- 

 phaga, Tamandua, and Cydoturus ; but appears to be unknown in a 

 fossil state. The jaws are entirely destitute of teeth ; the body is 

 clothed with hair ; the tail is long ; there are either four or five digits 

 in the pes ; and the third digit of the manus is the longest. 



Family Megatheriidce. — The members of this family are en- 

 tirely extinct, and are confined to the New World. They comprise 

 a number of very large forms adapted solely for walking on the 

 ground, and showing in their skeletal organisation characters inter- 

 mediate between the preceding and the following families. Thus, 

 while their vertebras and limbs are constructed like those of the 

 Myrmecophagidce, their crania and dentition resemble those of the 



Fig. 1165.— Megatherium americamun ; from the Pleistocene of South America. 

 Much reduced. 



Bradypodidce. One species of the genus Scelidotheiium approxi- 

 mates, however, in cranial characters to the former family ; and it 

 is probable that the whole three families have originated from a 



single stock. The number of the teeth is usually - ■ and the first 



4 

 and second teeth may be either in apposition or separated by an 

 interval. The femur has no third trochanter ; and the under sur- 

 face of the odontoid process of the axis vertebra presents a peculiar 

 flattened surface for articulation with the atlas. The type genus 

 Megatherium 1 is found in the Pleistocene of both South and North 



1 This name should properly be Megalotheruim, but its antiquity renders it 

 somewhat sacred. 



