lOlO.] Barythcriiiin; (he South American " Uiigulates." 369 



phyletic increase in body size the humerus early lost the entepicondylar 

 foramen and reduced the entocondyle; the femur originally may have had 

 the third trochanter nearly half A\ay down the shaft {Palceomastodon, cf. 

 Pantolambda) but in the Mccritherium line the third trochanter was lost. 



The family of perhaps Basal Eocene protungulate mammals having the 

 above-mentioned combination of characters would be hard to classify under 

 any known order and would probably be rather remotely related in various 

 degrees to the Meniscotheres, Phenacodonts, Mioclsenids, Periptychids, 

 and Pantolambdids. 



VII. The Barytheria (Incert^ Sedis). 



The remains of Bari/theriimi grave Andrews (1906, })1. xvii, figs. 4-9) 

 from the Qasrel Sagha (Upper Eocene) beds of the Fayllm, Egypt, are too 

 incomplete to afford decisive evidence as to the relationships of the order 

 Barytheria of Andrews with other orders. The molars are bilophodont and 

 in the worn dentition of the type, p ^ also may have been bilophodont 

 (p/. Mceritherium). The coronoid process of the mandible is very broad, 

 anteroposteriorly rectangular at top and extended forward externally to nig 

 {cf. Mccritherium). The anterior incisors are much enlarged and procum- 

 bent, and the scapula, also as in Mwritherium, has a large coracoid process. 

 The humerus however is rather analogous with that of Dinoceras, though 

 differing in the great development of the internal crest (Andrews). The 

 radius also resembled the Dinoceratoid type in its general form and in the 

 proportions of the scaphoid and lunar facets (Andrews). So far as it goes 

 the material tends to confirm the hypothesis that the Proboscidea, x\mbly- 

 poda and certain other orders have had a common origin. Ameghino's 

 suggestion that Bari/fherium is related to Pijrotherium has been disputed 

 with cogent evidence by Gaudry (1909, pp. 27, 28). 



VIII. The extinct South American groups Homalodotheria, 

 Astrapotheria, Toxodontia, Typotheria, Litopterna. 



Recent Classifications. 



1891-1893. Zittel. 

 [Order] Ungulata. 



[Suborder] Toxodontia. Fam. Homalodontotheridae, Astrapo- 



theridae Nesodontidae, Toxodontidae. 

 [Suborder] Typotheria. Fam. Protypotheridae, Typotheridae. 



