Peterson: Material Discovered in Uinta Basin. 103 



surface of the shaft, and reaches downward about one-third of the 

 length of the bone. The distal trochlea is deeply excavated, obliciue, 

 and the internal malleolus is well developed. 



The pes was found in an articulated position with the distal end of 

 the tibia in place. The long and slender structure of the limb, when 

 compared with Mcsohippus, is at once observed. The astragalus is 

 high and laterally compressed, the navicular and cuneiform are quite 

 high, the median metatarsal is especially slender, while the lateral 

 metatarsals are relatively heavier than in the Oligocene genus. There 

 is no evidence present of the first digit. The structure of each bone 

 of the pes is wonderfully similar in detail to that of the same bones 

 in Mesohippiis from the Oligocene. 



PSEUDOTAPIRS OF THE XoRTH AMERICAN EoCENE.*^^ 



While working upon the fossil tapirs of the Uinta Eocene in the 

 collection of the Carnegie Museum it became evident that a more 

 intensive study of the pseudotapirs of the earlier Eocene formations 

 was necessary. Types and other material representing " Systemodon" 

 = Homogalax^^ of the Wasatch and Wind River, Heptodon of the Wind 

 River, Helaletes hoops, H. nanus, Dilophodon minusculus " Isectoloplins'' 

 latidens and Desmatotherium guyotii of the Bridger, and Isectolophus 

 annectens of the Uinta were kindly submitted for this study by the 

 authorities of the Peabody Museum of Natural History, the American 

 Museum of Natural History and the Natural Science Museum of 



*8 An abstract of this portion of the present paper was read before the Pittsburgh 

 meeting of the Paleontological Society, 1917-18. 



*' "On The Names of Certain North American \"ertebrates," Science, Vol. IX, 

 1899, p. 593. 



In 1908 {Bull. Amer. Mus. Nat. Hist., Vol. XV, p. 241) Mr. Granger was under 

 the impression that the genus from the Bighorn, known as " Systemodon," species 

 tapiriniis (1881, Amer. Naturalist) though a much mutilated type, should be accepted 

 Since that time extensive and thorough field work by the American Museum parties 

 in New Mexican localities reveals the fact that not a single specimen of the 

 Bighorn " Systemodon" was found, and Mr. Granger is now inclined to believe, 

 according to a communication dated by him January 20, 1916, that this form 

 ''does not occur there and that the type of tapirinus is a horse {Hyracotherium, or 

 Eohippus as we call the American species)." In this connection I may further 

 quote a portion of Mr. Granger's letter: "It seems too bad to have to give up the 

 name Systemodon, it has become so firmly fixed in the literature, but there is no way 

 out of it that I can see. If by any chance we could use it, it would not be for the 

 form which we understand as Systemodon, but for a Hyracolhere, which I now feel 

 sure that it is." 



