196 CHORD ATA. 



A. NON-DECIDUATA. Placenta non-deciduate (except in some 

 Edentates). 



Order 1. Edentata (Bruta). Teeth of persistent growth and without 

 enamel ; median incisors never present ; grinding teeth, when present, 

 similar and rootless. 



(a.) Phytophaga, arboreal vegetable-feeding South American forms, 

 with dome-shaped deciduate placenta. Bradypus, three-toed sloth, with 

 tridactyle manus and nine cervical vertebrae. Choloepus, two-toed sloth, 

 with didactyle manus and six to seven cervical vertebrae. Megatherium 

 and Mylodon, gigantic ground sloths, from the South American Pleis- 

 tocene. 



(6.) Entomophaga, insectivorous forms. Myrmecophaga, great ant- 

 eater (S. America), and Manis, pangolin or scaly ant-eater (E. Africa 

 and S. Asia), both toothless, the former with a dome-shaped deciduate, 

 the latter with a diffuse placenta. Orycteropus, aard-vark (S. Africa), 

 with zonary deciduate placenta. Dasypus and Chlamydophorus, arma- 

 dilloes (S. America) with bony dermal plates covered by epidermic scales, 

 and discoidal deciduate placenta. Glyptodon, a large armadillo from 

 the S. American Pleistocene. 



