EOCENE AND OLIGOCENE TITANOTHERES OF MONGOLIA 



935 



at the symphysis, is quite unique; it betokens a 

 long, deep cranium of prodigious size. Unlike that 

 of its contemporaries, the coronoid is very broad; the 

 condyle is only moderately 

 elevated above the line of 

 the molar teeth; the angle 

 is small, not prominent; the 

 lower border is deeply de- 

 pressed below the grinding 

 series, then rises sUghtly 

 below the premolars and 

 sinks into the deep, power- 

 ful symphysis, which rises 

 like the incliaed straight 

 prow of a ship to the ele- 

 vated border of the cutting 

 teeth. These mandibular 

 characters are clearly dis- 

 played in the type (Am. 

 Mus. 20106) and in the 

 paratype (Am. Mus. 20107). 

 The extremely juvenile pair 

 of jaws (Am. Mus. 20115) 

 with its series of mUk teeth 

 displays only the swelliug 

 beneath the molars and the 

 very peculiar straight or 

 slightly concave chin. 



The cranial parts pre- 

 served above the maxillary 

 dental series display a high- 

 ly characteristic flattened 

 suborbital malar region, 

 wholly different from the 

 angulate or rounded malar 

 region of ProtitanotJierium 

 or of DolicJiorJiinus. Con- 

 sequently we await with 

 great interest a fuUer knowl- 

 edge of the cranium of 

 this large and peculiar ani- 

 mal, feeling quite confident 

 that it will display on a ti- 

 tanic scale characters simi- 

 lar to those of TelmatJierium 

 ultimum, last known of the 

 titanotheres of this phy- 

 lum in America. Like T. 

 ultimum, it shows many 

 signs of affinity with the 

 true dolichocephalic Meno- 

 dus ( = TitanofJierium) gi- 

 ganteus of North America. 

 These resemblances to 

 Menodus in the deep rami 



and deep chin are only partly sustained by the char- 

 acters of the cutting and of the grinding teeth. 

 101959— 29— VOL 2 39 



cutting teeth are 

 superior canines 



all 



Dental characters. — The 

 tremely prominent. The superior canines in the 

 males are like those of TelmatJierium and of Menodus 



Figure 790.- 



Jaws and maxiUae of type and paratype of Telmatherium bcrkeyi, 

 Irdin Manha formation (upper Eocene) 



Type maxiUa and lower jaw of a female individual (Am. Mus. 20106), lateral Tiew. Ai, Crown view of type superior 

 premolar-molar grinding series (Am. Mus. 20106). B, Crown view of paratype superior premolar-molar grmding series 

 (Am. Mus. 20121). Observe that the paratype grinders are somewhat more progressive than the type grinders in the de- 

 velopment of the tetartocones in the premolars, also in the deep invaginations anterior to the ectolophs in the molars. Bi, 

 Lateral aspect of the paratype male jaw (Am. Mus. 20107). Observe the deep symphysis, the straight, upward anterior 

 border of the symphysis, the enlarged male canines, and the enlarged male incisors. AU one-sixth natural size. 



= (TitanotJierium) in their prominent size and in their 

 laterally compressed crowns with trenchant edges 



