Douglass : Merycochcerus. ^7 



I defer these comparisons for my more complete memoir on the 

 Agriochceridce of Montana. It is sufficient to say here that this speci- 

 men differs in nearly every detail from the specimens from Nebraska. 



The So-called Merycochgeri from the Lower Madison 

 Valley, Montana. 



With regard to part of these specimens nothing final can be said 

 until the skulls or portions of them are found. The specimen named 

 Merycochcerus madisonius 21 looks very much like the mandible of Pro- 

 nomotherium laticeps. The associated upper jaw 22 is more like Mery- 

 cochcerus in having the anterior inferior origin of the zygomatic arch 

 farther forward than in the former. 



li Merycochcerus compressidens " ** in the form of the jaw more re- 

 sembles that of the type of Merycochcerus, but it may be something 

 else. 



The so-called Merycochcerus altiramus 2i should be put in the genus 

 Pronomotherium as a skull in the American Museum of Natural History 

 shows no generic distinction from the type of Pronomotherium. 



Cope's Merycochcerus obliquidens^ evidently does not belong to 

 either of these genera. 



IV. Affinities of Pronomotherium. 

 I do not know of anything very closely related to Pronomotherium 

 laticeps except Pronomotherium altiramus and ' ' Merycochcerus 

 rusticus. It may be from beds later than Merycochcerus proprius but 

 probably not a direct descendant. It is doubtful if it is a descendant 

 of "Merycochcerus" rusticus, but it was probably more nearly con- 

 temporaneous with the latter, than with the former. I know of 

 nothing in lower horizons which is likely to prove ancestral to any of 

 these. 



Pronomotherium was an extremely aberrant artiodactyl. The 

 upper lip and snout were certainly greatly modified to correspond with 

 the extreme modification of the bones of the head. The character 

 of the skull could hardly tell in a plainer manner, that the possessor 



21 " New Species of Merycochcerus," Am. Jour. Sci., Vol. XI., 1900, p. 75> 

 Fig. 2. 



vibid., p. 77- 



**lbid. t p. 79, F »g- 4- 



2*f6u/., p. 73» Fi S- *• 



""The Vertebrate Fauna of the Ticholeptus Beds," Atner. Nat., XX., p. 368. 



