XENARTHRA. 543 



Most of them are insectivorous (anteaters and armadillos), 

 a few are phytophagous (sloths). Many of them are burrowing 

 animals, but a few are arboreal. At the present day they are 

 confined to Africa, Asia and America. They are first fomid 

 fossil in the U. Cretaceous of Patagonia (Ameghino), and are 

 supposed to have relations through the Ganodonta and Tillo- 

 dontia (see below), with the early Carnivora and Rodentia, but 

 this is a highly speculative view. 



The Edentata may be divided into two main divisions — the 

 Xenarthra and the Nomarthra. The Xenartlu-a comprise all 

 the American forms, viz., the anteaters {Vermilingvia), the 

 sloths {Tardigrada) and the armadillos {Loricata) with the 

 extinct Glyptodontidae. The Nomarthra are the Old-World 

 forms, Orycteropus and Manis. The New- World forms (Xenar- 

 thra) undoubtedly constitute a natural group, inasmuch as the 

 extinct ground sloths connect the apparently diverse sloths and 

 anteaters. This cannot be said of the Old- World genera Manis 

 and Orycteropus. It is difficult to see in what fundamental 

 points these show special affinity either to each other or to 

 the Xenarthra. There is an immense number of extinct forms 

 belonging to the Xenartlu-a, some of them very remarkable, 

 e.g. the JMegatheriidae or ground sloths, and the Glyptodontidae 

 or extinct armadillos. These are all, like tlieir living allies, 

 confined to the New- World.* They date from the Eocene or 

 U. Cretaceous of S. America. 



Xenarthra. 



With additional articulating processes on the posterior dorsal 

 and on the lumbar vertebrae ; the scapula has a second spine ; 

 the ischia are united to the part of the sacrum formed by the 

 anterior caudal vertebrae ; the testes are in the abdomen between 

 the rectum and the bladder, the penis is small, the uterus simple, 

 and the placenta dome-shaped (the chorion being complete). 

 They are exclusively American and mainly S. American, one or 

 two forms extending into the southern part of N. America. 

 Necrodasypus Filhol, from tlie Eocene of France, has been as- 

 signed to the Xenarthra, but the remains are too incomplete for 

 certainty as to their systematic position. 



* Grandidier (Bull. Mus. Paris, 1901, p. 54) has described the re- 

 mains of a grovind sloth, which he calls Bradytherium, from Madagascar. 



