0. C. Marsh — Description of Miocene Mammalia. 409 



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 

 imperfectly from fragmentary portions, but the extensive 

 material already referred to has enabled the writer to make out 

 their entire 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 second and fifth. 



Elotherium clavum, sp. nov. 



On Plate IX, figure 1, is shown a skull of Elotherium, with 

 the brain cast in position, which agrees in many respects with 

 the skull figured on the preceding plate, and described above. 

 When first figured, the former skull was referred to E. crassum 

 (Dinocerata, p. 65, 1884), but a more careful comparison 

 proves it to be distinct. It is considerably smaller than E. 

 crassum, and the malar process is quite slender and tapering 

 below. It extends directly downward, and hence is not seen 

 in the top view of the skull. The length of this skull is six- 

 teen inches, measured from the front of the premaxillaries to 

 the back of the occipital condyles. The dentition agrees, in 

 the main, w T ith that of E. crassum, the last lower molar in 

 each having four cones only, and no heel. The malar arch 

 and the dependent angle of the lower jaw T will distinguish it 

 from E. Mbrtoni. The type specimen here figured is from the 

 Oreodon beds, near the White river, in southern Dakota. 



Ammodon Leidyanum, gen. nov. 



The teeth represented on Plate IX, figures 2 and 3, indi- 

 cate a very large animal belonging to the same group as those 

 last described, but differing in several respects. The first 

 tooth, shown in figure 2, is the type specimen of Elotherium 

 Leidyanum, already described by the writer.* It is the fourth 

 premolar of the right lower jaw, and was found in 1867, in a 

 Miocene deposit in Monmouth county, JS". J. 



* Proc. Phila. Acad., vol. xxii, p. 3; and Geology of New Jersey, p. 740, 1868. 



