168 J. B. Hatcher — Recent and Fossil Tapirs. 



humerus as those of Elasmognathus. Our material does not 

 enable me to add anything to what Wortman and Earle have 

 already made known respecting the structure of the carpus. 



Measurements of JProtapirus validus. 



mm 



Length of skull from base of canine to occipital condyle. . 242 



Length of frontals and parietals __ 151 



Distance between postorbital processes of frontals 73 



Greatest length of lower jaw 227 



Depth of jaw below pm. 2 33 



« " " 4 46 



Length of inferior diastema 32 



" superior " _ 27 



" " premolar molar series 102 



" " molar series 53 



" inferior premolar-molar series 102 



" " molar series ._ _ 57 



" humerus __. 203 



Breadth of distal end of humerus 41 



Length of radius 158 



Breadth of proximal end of radius 32 



Breadth of distal end of radius 29 



Length of ulna 216 



Height of olecranon process above articular surface 40 



Protapirus simplex W. & E. 



This species is known only from the superior premolars and 

 fragments of the lower jaw. There is in our collection a 

 lower jaw (11165), with the inferior dentition and both rami 

 nearly complete, found by Mr. H. F. Wells in the Protoceras 

 beds, in the same locality as the material just described. Not- 

 withstanding the horizon in which this specimen was found 

 on account of its size and the structure of the premolars I 

 refer it to Protapirus simplex. It is smaller than the jaw 

 referred to P. validus, and the premolars are in a less 

 advanced stage, the postero-internal cone being quite rudimen- 

 tary. It differs, also, from P. validus in that the cross-crest 

 on pm. 4 is in advance of the same element in pms. 2 and 3, 

 while just the opposite is the case in the latter species. A 

 further structural difference is noticeable in pm. 2 ; in this 

 tooth in P. validus the ridge, which runs forward from the 

 postero-external cone, unites with the antero-external, while 

 in the present specimen it unites with the antero-internal. 

 The principal dental characters of this specimen are shown in 

 figs. 5 and 5a, plate III ; the last molar is dropped down in 

 each to accommodate the figures to the size of the plate. 



