the Genera of Oreodontidce. 



283 



of the lacrymal bone on the front of the orbit. The zygo- 

 matic arch is decidedly light more so than in any of the 

 closely related forms, and has no tendency to thicken 

 along the rear margin, but continnes as a thin plate into 

 the lambdoidal crest. The sagittal crest is also light and 

 low. 



The tympanic bullae are small and not inflated. The 

 auditory meatus is inclosed in a bony tube of moderate 

 length and opens obliquely upward, but not nearly as high 

 up as in either Merycochoerus or Promerycochoerus, 

 The mastoid plate is but moderately expanded. The pre- 

 maxillae are small and fused in the median line. 



The dentition is not very distinctive, the teeth being 



Fig. 1. Skull of Ticholeptus rusticus from the side, 2/5 nat. size. 



moderately hypsodont, the molars increasing in size from 

 front to back. The premolars are crowded so that in the 

 upper jaw the first three stand obliquely in the maxilla 

 bone. The canines are small and the only gap in the den- 

 tal series of either jaw is the small interval between the 

 canine and first premolar. 



Most of the characters of the skeleton appear in the 

 restoration, for which I had the skull, pelvis and scattered 

 vertebrae and most of the fore limb as one associated 

 specimen. The other parts are drawn from some twenty 

 other finds two of which represented considerable por- 

 tions of the skeleton associated. There was no complete 

 back bone but vertebrae from every portion of it including 

 the sacrum. The upper part of the femur was preserved 

 in none of my material and is restored. Otherwise all the 

 bones are drawn life size from one or another specimen 

 and the whole photographed down. The pelvis is the only 



