380 E. L. Troxell — Entelodonts in Marsh Collection. 



able features is the long dependent process (m) on the malar 

 bone, which in this species extends downward to the inferior mar- 

 gin of the lower jaw, in front of the angle. This is the case when 

 these processes are somewhat expanded transversely, as shown in 

 figures 2 and 3, which represent the skull as it lay in the matrix. 

 Another peculiar feature shown in figure 1 is the series of pro- 

 cesses on the lower jaw, the first (a) being the dependent, everted 

 angle of the ramus; the second (b) a protuberance under the 

 third lower premolar ; and the third (c) a process below the base 

 of the canine. These processes are well shown, also, in figure 3. 



"Seen from above, in figure 2, the most noteworthy features 

 are the small space occupied by the brain in the parietal region 

 (p), the widely expanded malar processes (m), and the narrow, 

 elongated facial portion. In this figure, the lower jaw is not. 

 represented. In figure 3, which shows the skull and lower jaws 

 in position and seen from in front, many interesting points are 

 shown. Copies of the original drawings of figures 1 and 2 will 

 be found in von Zittel's Palaeontology, Vol. IV, p; 337. 



"The feet of Elotherium have hitherto been known only im- 

 perfectly from fragmentary portions, but the extensive material 

 already referred to has enabled the writer to make out their en- 

 tire structure in the present species. In figures 4 and 5 of Plate 

 VIII, the manus and pes are represented, one-sixth natural size. 

 It will be seen that in each foot there are only two functional 

 digits, corresponding to the third and fourth in man. The first 

 digit is entirely wanting, and only remnants remain of the sec- 

 ond and fifth." 



It is important to note that this is the specimen often 

 mentioned in the literature as the apotype of A. crassum 

 (iig. 9). It is the purpose in this chapter to point out 

 the differences between it and A. crassum, and to give this 

 well-known specimen a separate specific designation. 



In its whole structure, except in the body of the ramus 

 and in the size of certain premolars, which are quite rudi- 

 mentary, the skull is robust, heavy, and massive. The 

 stout-rooted canines, the thick and wide process from the 

 jugal, the mental tuberosities, all indicate this. 



The zygomatic arch is a structure of great strength ; the 

 dependent process, measured from the temporal suture, 

 has a length of 140 mm., which is 34 mm. less than that of 

 the holotype of A. crassum, while at the same time the 

 width of 62 mm. is greater by 10. Thus the slenderness 

 of the present specimen is 44.3 per cent; that of A. cras- 

 sum holotype is 30 per cent. 



From the eye socket the lengths of the processes in the 

 two specimens are about equal, some 200 mm. The pro- 



