SUBORDER B XENARTHRA 91 



tarsals. The terminal phalanges are sometimes claw-like, sometimes broad 

 and hoof-like, as in Glyptoclontia. 



The. brain-case of the edentates is of moderate size ; the brain of the several 

 families differs considerably, however, in that the cerebrum may be either 

 smooth or furrowed and the corpus callosum small or large. 



In Old World forms the genital organs recall those of the Ungulata. 

 The testicles are situated in the groin. The penis is external, the uterus 

 is bicornuate, the vagina is undivided and the placenta is diffuse or broad and 

 zone-like. American edentates have the testicles in the abdominal cavity 

 between the rectum and bladder, the penis is small, the uterus is globular, 

 and the placenta dome-shaped. The Old World forms are grouped as 

 Nomarthra, and American edentates are designated as Xenarthra. 



Suborder A. NOMARTHRA Gill. 



The Old World edentates are distinguished by the simple articulation of 

 the dorsal and cervical vertebrae. The family Oryderopodidae is represented 

 in the Lower Pliocene of Bessarabia, Samos and Pikermi by a fossil form, 

 Oryderopus gaudnji Forsyth Major, and also by a humerus (Palaeoryderopus 

 quercyi Filhol) in the Phosphorites of Quercy. This horizon yields also the 

 skull of Leptomanis edwardsi, and the humerus, femur and tibia of Necromanis 

 quercyi Filhol. A form somewhat resembling Oryderopus, and also Manis, 

 known as "Lutra" franconica Quenstedt, from the Miocene fissure deposits of 

 Solenhofen, is called Teutomanis and Galliaetatus by Ameghino. 



A metacarpal of very similar conformation is also known from the 

 Miocene of Mont Ceindre, near Lyons. The indications are, as far as these 

 incomplete remains show, that the apparently widely separated families of 

 Oryderopodidae and Manidae, on the one hand, and the Dasypodidae, on the 

 other, have a common ancestor. 



Suborder B. XENARTHRA Gill. 



The Xena/t'thra, distinguished by the accessory articulation of the posterior 

 dorsal and cervical vertebrae, comprise two "tribes " or subdivisions : (1) the 

 Anicanodonta, without or, at the most, with only vestigial dermal armour, and 

 (2) the Hicanodonta, with a covering of bony or horny plates. 



Tribe 1. ANICANODONTA Ameghino. 



Of the families which constitute this tribe the Myrmecophagidae and 

 Bradypodidae are represented only by very incomplete remains in the Pleistocene 

 of South America. The extinct family Gravigrada is abundantly represented 

 by fossil remains in the Tertiary of Patagonia and in the Pleistocene of 

 South America. In North America this family is confined to the Pliocene 

 and Pleistocene. It may have originated from the Taeniodontae of the Early 

 Eocene of North Amexnca. 



Family 1. Taeniodontae Cope. {Ganodonta Wortman.) 



The number of I always reduced, large, P and M iisually with roots, and 

 more or less completely covered tvith enamel. Vertebral articulation rather simple. 

 Lower Eocene of North America. Puerco to the Wind River beds. 



