CONDYLARTHKA. 397 



Measurements of humerus. 



No. 1. 



M. 



Total length with iiauge 13& 



Length to distal end of bicipital ridge 076 



Transverse diameter of head with greater tuberosity (extended by pressure) 039 



Diameters of shaft at inferior extremity of bicipital ridge \ anteroposterior 022 



( transverse 0. 15 



Diameters of humerus below do J ^''^'^™P°^*«"°'^ ^^^ 



f transverse 018 



Width at epicondyles 055 



I tranverse 033 



Diameter condyles anteriorly ■? < roller 015 



( anteroposterior) flange 013 



Length of end of ex^icondyle 022 



The ulna is stout and compressed throughout its length; its vertical 

 diameter not diminishing much distally. The olecranon is compressed so 

 as to be in a vertical plane ; the superior edge being acute, and the inferior 

 rounded, and becoming wider near the extremity, where it rises obliquely 

 inwards. The external side of the humeral cotylus is a little, the inner side 

 more, convex. The flanges of the humeral cotylus of the ulna are peculiar. 

 The posterior is only developed on the internal side of the shaft, and does 

 not exist on the inner side. This is the condition in Coryphodon, but the 

 external is present in Phenacodus and Hyrax. It is wanting in Carnivora, 

 but the internal is smaller in them than in Periptyclms. The radial contact 

 is entirely flat, and there is no anterior flange except on the external side. 

 It is here horizontally extended, but not vertically, as is the case in Carnivora. 

 There is a longitudinal groove on the external side of the shaft near the su- 

 perior margin, which soon terminates. A much wider groove, with defined 

 inferior edge, commences below the radial facet, on the inner side of tlie 

 shaft, and extends along the latter, becoming wide and shallow. The radius 

 has the proximal half of its shaft quite slender, more so than in Phenacodus 

 primcevus or wortmani, and there is no bicipital tuberosity. The head ex- 

 pands abruptly from the shaft, and the humeral face is transverse. It is 

 not much recurved at the internal and wider extremity, while the external 

 or narrower extremity is obtuse and rounded. The anterior foot is unfor- 

 tunately unknown. 



