240 Bulletin American Museum of Natural History. [Vol. XIII, 



m^. It is also possible that it represents an ancestor of R. san- 

 saniensis, which is placed in the CeratorhincR below. It certainly is 

 not Teleoceras aurelianensis, and it apparently cannot be referred 

 to Aceratherium platyodon j these are the only strictly Lower Mio- 

 cene (Burdigalien) Rhinoceroses hitherto described in France. 



Subfamily, ACERATHERIIN.^. PHYLUM II. 



Large Oligocene and Miocene Rhinoceroses of Etirope ; dolichocephalic with 

 long, narroiv nasals ; smooth or tvith rudimentary horns at sides of the tips ; 

 f rentals finally developing horns ; large cutting teeth ; relatively persistetit tet- 

 radactyl manus ; long-limbed . 



Contemporary with the small Diceratheres is this phylum of 

 large Rhinoceroses which appears to rise in a large but primitive 



species in the Lower Oligocene, A. 

 filholi, and pass through A. lem- 

 anense and A. tetradactylum into A. 

 incisivum of the Lower Pliocene, 

 which in turn is possibly the ances- 

 tor of Elasmotheriutn and the Elas- 

 motheriinae. The European Lower 

 Oligocene Acerathere is exactly 

 similar in size to A. platycephalum 

 Osborn, which is possibly the 

 American representative of this 

 type ; but it differs widely in the 

 mode of transformation of the upper premolar teeth ; for this 

 reason it is referred to a new species. 



I. Lower Oligocene. 



Phosphorites^ Quercy, Cazark, Escamps. 



Aceratherium filholi/ sp. nov. 



Type : Left maxilla containing second premolar to third molar inclusive ; 

 Paris, Coll. Rossignol, Loc. Phosphorites. Cotype ; Paris, lower jaw, contain- 

 ing pm*, pm*, and m^ (Figs. 7, %A). 



Definition : Large upper premolars, simple, unlike molars, with incompletely 

 formed creSts ; upper molars with internal cingulum and strong protoconule fold, 

 small antecrochet,no crochet ; depression in posterior face of metaloph of third 



Fig. 7. Aceratheriutn filhoii. Co- 

 type : Paris. Lower third and fourth 

 premolars and first molar. 



' Dedicated to my friend M. Henri Filhol, who has contributed so extensively to our knowl- 

 edge of the fauna of the Phosphorites. 



