igoo.] O shorn, Phytogeny of the Rhinoceroses of Europe. 25 I 



as the stout cylindrical protocone. Occiput broad, in a vertical 

 plane ; jaw with a decided angle. Front view of nasals is very- 

 characteristic (Fig. 12, Z>), a rugosity appears upon each tip with a 

 cleft between (as in T. fossiger); there is also a very slight swell- 

 ing and faint rugosity upon the frontals immediately above the 

 eyes which may indicate the rudiment of a median horn. As 

 compared with the Aceratheriinge the fore and hind limbs and 

 feet in the Paris Museum are relatively short, but they are longer 

 than those of its Upper Miocene relative T.fossiger mounted be- 

 side them ; this species is also distinguished by narrower pre- 

 molars. (2) A fine lower jaw (Loiret) exhibits premolars with 

 flattened outer wall, also a very small, single-fanged pmj. (3) The 

 maxillary series (Coll. Vibraye) above alluded to shows a cement 

 layer on the molars as in some Upper Miocene American types. 



Lartet in a letter to Nouel expressed the opinion that this spe- 

 cies was identical with the Middle Miocene T. brachypus. A 

 close comparison of the teeth of these two species in the Paris 

 Museum reveals the following resemblances and differences : 



T. aurelianensis. T. brachypus. 



Premolars broad 



Antecrochet strong in p3, p4 



Metaloph of p* long 



Molars, internal cingulum wanting 



Premolars broad 

 Antecrochet reduced or wanting 

 Metaloph of p* long 

 Cingulum strong 



2. Middle Miocene Stage. 

 Simorre, Sansan (?). 



T. brachypus Lartet. — Paris : A fine maxillary series from Simorre, Gers 

 (Coll. Lartet No. 2386); fourth superior premolar (p*) compressed antero- 

 posteriorly and extending transversely more than in T. aurelianensis ; superior 

 molars with strong internal cingula ; inferior molars with extremely flattened 

 outer faces ; enormous upper incisors. This species is generally said not to 

 occur at Sansan, but a single lower canine tooth (catalogued Ji. tetradactylum, 

 Paris Museum) probably represents it on this level. 



3. Upper Miocene Stage. 



Grive- St. -Alban, Steinheim. 



T. brachypus. — The finest examples of this species are found 

 in the Museum d'Histoire Naturelle of Lyons and have been 

 described and figured by Deperet. Relying upon his determin- 

 ation ('87, p. 178) we observe the following dental characters : 



