690 MAMMALIA. 



ally divided by a median partition, the placenta is a deciduate dome- 

 shaped disc. One young one is born at a time. 



2. MegatheriidcS or Ground Sloths extinct forms of large size, inter- 



mediate between the sloths and the ant eaters. Their remains 

 are found in Pleistocene deposits in N. and S. America. 

 Megatherium exceeded the Rhinoceros in size. 



3. MyrmecophagidcE the Ant Eaters, hairy animals, without even 



traces of teeth, with long thread-like protrusible tongues, viscid 

 with the secretion of greatly enlarged submaxillary glands. One 

 form, Myrmecophaga jubata, is terrestrial, the others, belonging 

 to the genera Tamandua and Cycloturus^ are arboreal. All 

 feed on insects. All are Neotropical. The skull is long ; the 

 third finger is greatly developed, the others are small ; the pes 

 has four or five almost equal clawed toes ; the clavicles are 

 rudimentary ; the tail is long and sometimes prehensile. The 

 brain is well convoluted. The uterus is simple. The placenta 

 is dome-like or discoidal. 



4. Dasypodidae the Armadillos, all S. American except Tatusia 



novemcincta, which extends as far north as Texas. They are 

 nocturnal, omnivorous animals, able to run and burrow rapidly. 

 They are unique among living mammals in having a dermal 

 armature of bony scutes united into shields and rings, and 

 covered by horny epidermis. The teeth are numerous, simple, 

 and of persistent growth. Clavicles are well-developed. The 

 digits have strong claws or nails. The brain has large olfactory 

 lobes ; the cerebral hemispheres have few convolutions. The 

 tongue is long and protrusible, and the submaxillary glands 

 are large. The stomach is simple. The uterus is simple. 

 The placenta is discoidal and deciduate. 



Examples : Dasypus^ Chlamydophorus^ Tatusia. 



5. Glyptodontidoe extinct Pleistocene types, mostly S. American, but 



represented in Mexico and Texas. The body was often huge, 

 and was covered by a solid carapace of great strength, " Why 

 such a form as the Glyptodon should have failed to keep his 

 ground is a great mystery ; nature seems to have built him, as 

 Rome was built, for eternity." (W. K. Parker.) 



6. Manidse the Ethiopian and Oriental Pangolins, covered dorsally 



with overlapping horny scales. They are terrestrial, burrowing 

 animals, but sometimes climb trees. They usually feed on ter- 

 mites. Teeth are rudimentary, the tongue is long and pro- 

 trusible. The uterus is bicornuate, the placenta diffuse and 

 non-deciduate. There is one extant genus Manis. 



7. Orycteropidae the Ethiopian Aard-varks, represented by two 



species of Orycteropus, ranging from S. Africa to Egypt. 

 They are shy, nocturnal animals, living in burrows, feeding 

 on termites. There are numerous complex teeth. The skin 

 bears scanty bristles. The mouth is tubular, and the tongue 

 is narrow and protrusible. The digits bear nails suited for 

 digg m g- The uterus is bicornuate, the placenta broadly 

 zonary. 



