932 



EOCENE AND OLIGOCENE TITANOTHERES OF MONGOLIA 



Measv7-ements, in millimeters, of skeletal remains referred to 

 Proiitanotherium 



' Belonging to more than one individual. 

 ' Belonging to one individual. 

 ' Estimated. 



ProtitanotJierium grangeri. — The tibia is also short in 

 this specimen of P. grangeri (Am. Mus. 20171, belong- 

 ing to more than one individual), the articular length 

 being about 350 millimeters (1 foot 2 iuches), as com- 

 pared with an articular length of about 400 millimeters 

 (1 foot 3}i inches) in a specimen (Am. Mus. 20277, 

 belonging to one individual) referred to Protitanothe- 

 rium mongoliense. 



ProtitanotJierium mongoliense. — The left hind limb 

 of one individual referred to P. mongoliense (Am. Mus. 

 20277), including femur, patella, tibia, and complete 

 tarsus, has a length of 1,400 millimeters (4 feet 7 

 inches) when completely stretched out. The three 

 metatarsals are rather slender, the median one, Mts 

 III, having a complete length of 7 inches, whereas the 

 median metacarpal (P. mongoliense?, Am. Mus. 20274, 

 more than one individual) has a median articular 

 length of 7K inches. Am. Mus. 20277 (one individ- 

 ual), in which the superior articular length of the 

 femur is 650 miUuneters (2 feet 2 inches) and the arti- 

 ular length of the tibia about 400 millimeters (1 foot 

 3J^ inches), is distinctly titanotheroid. 



A manus (Am. Mus. 20258) has a median metacar- 

 pal articular length of 18 millimeters, such as we should 

 naturally attribute to the manus of P. mongoliense. 



ProtitanotJierium andrewsiP. — The series of larger 

 associated metapodials of one individual from the 

 Shara Murun formation bears the number Am. Mus. 

 20259 and, although abbreviated at the distal extremi- 



ties, so far surpasses in size the measurements of P. 

 mongoliense? (Am. Mus. 20274) that it may be 

 attributed to the larger species ProtitanotJierium 

 andrewsi. The massive humerus (Am. Mus. 20327) 

 found in the Shara Murun formation has an articular 

 length of 454 millimeters (1 foot 63^ inches). It is 

 distinctly titanotheroid in structure, with very broad, 

 high, bicipital crest. This large humerus also may 

 well belong to the more progressive species P. 

 andrewsi. 



Pro-Menodus pJiylum sp.f. — In the Shara Murun 

 formation occurs also an extremely long, slender- 

 limbed species of animal represented by a femur 

 (Am. Mus. 20253). This femur is actually as long 

 (680 mm.) as that referred above to ProtitanotJierium 

 mongoliense (Am. Mus. 20277), but it is far more slen- 

 der — in fact, too slender to belong to any known species 

 of titanotheres unless it be to the line of the ancestral 

 slender-limbed Menodus. With it is a long, slender 

 right ulna (402 mm.) and a number of slender spine 

 dorsal vertebrae, a limar, and one metapodial. If 

 compelled on this meager evidence to place this species 

 in its proper phylum, we should be inclined to describe 

 it as an ancestral form of the Menodus mongoliensis of 

 the Ardyn Obo formation. The ulna is much less 

 elongate than in the long, slender-limbed ancestors of 

 BalucJiitJierium. A tibia of similarly long, slender pro- 

 portions (Am. Mus. 20327B) may represent a long- 

 limbed titanothere of the Menodus rather than of the 

 robust Brontops type. 



There are other remains of the limb skeleton from 

 the Shara Murim formation — part of the pes (Am. 

 Mus. 20274), foot bones (Am. Mus. 20327a, b, c, d, 

 etc.)^which must await specific determination until 

 further evidence is afforded by additional material. 



Conclusion. — On comparing the above measure- 

 ments and preliminary description of the limbs of 

 ProtitanotJierium grangeri, P. mongoliense, and P. 

 andrewsi, we observe a progressive increase in length 

 and in massiveness which is harmonious with the 

 progressive increase in size of the crania of these three 

 species of titanotheres. 



In these, as in the American titanotheres, the 

 humerus and ulno-radius are subequal in length and 

 the femur is relatively much longer than the tibio- 

 fibula. These proportional measurements again agree 

 closely with those found in the American titanotheres. 



SUBFAMIIY TEIMATHERIINAE 



Telmatherium Marsh, 1872 



Generic cJiaracters. — The generic characters of this 

 deep-jawed Mongolian titanothere are inferred only 

 from the gigantic type jaw and inferior and superior 

 dentition of TelmatJierium ierJceyi and of six other 

 specimens discovered in the Irdin Manha formation. 

 As the entire upper and posterior portion of the 



