SUBORDER C 



ENTELONYCHIA 



239 



without roofs, covered with enamel on all sides, but the outer surface interrupted by 

 bands in which the enamel is lacking. Astragalus with flattened trochlea. 



Toxodontherium Ameghiiio. (Haplodontherium Ameghino.) 



3.1.3.3. 



3.1.3.3.' 



Upper premolars and molars still rather broad. Pampas formation, Argentina. 



2.1 4.3. 

 Xotodon Ameghino. ^ , . — • Both occur in the Pliocene and Pleistocene 



of Argentina. 



3.1.4.3. 



Toxodon Owen (Fig. 324). 



2.0.3.3. 

 3.1.4.3. 



The largest member of the suborder, 



Fig. 324. 



Toxodon burmnsteri Giebel. Pleistocene (Pampas Formation), Lujan, Argentina. A, Skull and lower jaw. 

 1/7. -B, Upper first and second molars, grinding surface. C, Lower third molar, grinding surface., (After 

 Burmeister.) 



exceeding the rhinoceros in its dimensions. Nasals short, nostrils rather 

 remote. Pliocene and Pleistocene (Pampas formation) of Argentina and 

 Bolivia. T. platensis Owen. 



Suborder C. ENTELONYCHIA Ameghino. ^ 



[Ancylopoda, Tillodontia Ameghino.) 



Extinct, plantigrade or semidigitigrade herbivores with complete, seldom reduced 

 dentition. Incisors, canines and premolars either passing into one another, or in 

 both the upper and lower jaws one incisor strongly developed. Lower canine some- 

 times resembling an eye - tooth. Premolars and molars lophodont, varying from 

 brachyodont to hypsodont type and always with roots. Premolars simpler than the 



^ Ameghino, Florentino, lilnumeratiou syiioptique des mauimiferes fossiles de Patagouie. 

 Buenos Aires, 1894. — Sur les ongules fossiles de I'Argentine. Revista de Jardin zoologico Buenos 

 Ayres, 1894. — Notices preliminaires sur des ongules des terrains cretaces. Boletin Acad. Nacional 

 de Cienc. de Cordoba, vol. xvi., 1901. — Flower, W. H., Homalodontotherium. Philos. Trans., 

 1874. 



