78 Douglass — New Species of Meryeoehoerus in Montana. 



Merycochcerus elrodi n. sp. 

 Kepresented by part of the posterior portion of a left man- 

 dibular ramus with the last two molars. This, so far as they 

 can be compared, most resembles M. madisonius, but I do not 

 think they belong to the same species. The only portions 

 common to the two are m 2, the anterior lobe of m 3 and the 

 portions of the rami beneath, and here there are no points of 

 exact likeness. In the present species the crowns of the teeth 

 are higher, though this is partly due to a less amount of wear. 

 There is no bridge or buttress uniting the inner lobes in ra #. 

 This tooth is longer and narrower in this specimen. There is 

 a cingulum on the anterior face also on the front of m 3. The 

 ramus is deeper but not so thick, the difference being more 

 marked near the lower border. The lower border of the jaw 

 is less flat and has an angular ridge near the outside border. 

 The crescent-shaped convexity on the outer face is not seen but 

 under m 1 the jaw is nearly flat. 



The contour of the lower 

 border of the jaw differs 

 from that of M. laticeps. 

 The descent to form the 

 f//yjL. . anterior part of the rounded 



"'^Kyp^y . ry<\-:' K — "~"~~l angle is farther back, and 

 y /^ ky.%,^ j the ramus does not become 

 so deep. The masseteric 

 fossa had evidently about 

 the same position and shape 

 as in M. altiramus. A 

 shallow depression or groove 

 extends downward and for- 

 ward from it to the middle 



Merycochcerus elrodi x|. mi J ,...,' 



Inere are traces ol a similar 

 groove in M. Zatieeps and M. altiramus. 



Measurements. 



M. 



M 2, length -027 



M 2, width -017 



M 3, length „.. _. -041 



M 3, width _ -020 



M 3, height, about -030 



The name is proposed in honor of my friend Prof. M. J. 

 Elrod of the State University of Montana. 



From fragment of indurated clay that had rolled from cliff 

 near top of Big Eound Top, east side of lower Madison Valley, 

 about seven miles south of Logan, Montana. Found by the writer. 



