MAMMALIA 



397 



as very 



in South America, reaches a length of about two feet. It h 

 large front claws. 



The sloths {Bradypodidae), found only in the New World, are 

 arboreal forms, never descending to the ground if possible. They 

 are nocturnal feeders and their hair usually contains quantities of 

 green algae, causing them to resemble branches. The three-toed 

 sloth has nine cervical vertebrae, while the two-toed sloth has six 

 instead of the seven usually found in mammals. 



/i 



>-»^: ' • '■■■ ;■.'*- 



^ 



Fig. 225. Giant ant eater. (Courtesy of N. Y. Zool. Sec.) 



The three-banded armadillo {Dasypodidae) of Argentina is able 

 to close itself into a tight round ball so that it resembles a nut. 

 The nine-banded armadillo is somewhat larger and is found ranging 

 from Texas to the central part of South America. It has been 

 studied recently at the University of Texas, since it offers a most 

 interesting example of quadruplets, identical of course. Armadillos 

 eat insects and worms, and occasionally salamanders and lizards. 



Fossil Relatives of the Edentata. — Fossil remains of the modern 

 sloths and ant-eaters are unknown, but the extinct ground sloths 

 {Megatheriidae) with the head and teeth of a sloth and the tail of an 

 ant-eater were found in the Pleistocene, one species having reached 

 the length of nearly twenty feet. A large armadillo-like form known 

 as Glyptodon was found in the Pliocene of the Americas. 



Order VIII. Ungulata. — Terrestrial, usually herbivorous, nearly 



