BIG BADLANDS OF SOUTH DAKOTA. 



491 



anterior border of p4 (Fig. 20). It is smaller than Entelodon 

 magnum, from which it also differs in having the posterior part of 

 P3 less broad and the inner half of p4 narrower anteroposteriorly, 

 so that the anterior border curves backward and inward. On the 

 opposite side from that figured this border is slightly more concave 

 than I have drawn it, but on neither side is there anything like the 

 deep notch seen in ArchccotJieriiiin and Scaptohyus. In the oblique 

 position of pi_ behind the canine and the spacing of the anterior pre- 

 molars, the specimen resembles Archccotherium, but in the structure 

 of p4 it represents a distinct departure from all the American genera. 

 As skull characters are not available, I refrain from giving it a 

 name. It is a shorter-faced form than M egachccrus and has the 

 lateral incisor erect instead of procumbent. Still another, but very 

 much larger, animal, apparently distinct from the forms just de- 

 scribed from the Protoceras beds, is represented by various frag- 

 ments. 



Habits of Entelodons. 



Apart from the digging proclivities of Scaptohyus, already de- 

 scribed, one of the most clearly indicated habits of the entelodonts 



Fig. 31. Archwotherium wanlessi sp. nov. Holotype, No. 12522. Right 

 side of the ant-orbital tract showing injury, one half the natural size. 



