OF WESTERN NORTH AMERICA. 



113 



LOWER MIOCENE— Continued. 

 ROBENTIA-Continued. 



LEPORIDiE. 





1. 



2. 



3. 



4. 



5. 







2. 



3. 



Lepus primigenius Matthew . 

 Lepus macrocephalus Mat- 

 thew 









X 



X 





Lepus macrocephalus Matthew. 







X 



Diceratherium cooki Peter- 

 son 



Diceratherium niobrarense 

 Peterson 



Diceratherium sp 



Moropus ? elatus Marsh. 



Parahippus aff. crenidens 

 Scott 



Parahippus sp 



Parahippus spT 



Anchitherium sp 



"Miohippus annectens 

 Marsh" 



'Miohippus equiceps Cope". 



PERISSODACTYLA. 



Rhinocerotid^. 



/ Diceratherium sp. 



I X I 



X 



C.HALICOTHERIID^ . 



! I || Moropus ? elatus Marsh. 

 Equid^. 



•I I X I 



Parahippus ne))rascensis Peter- 

 son 



Parahippus sp 



Parahippus sp 



Dinohyus hoUandi Peterson. 

 Elotherium sp 



Desmathyus siouxensis (Pe- 

 terson) 



ARTIODACTYLA. 



Elotheriid^ (=Entelodontid^). 







!^l 



Ixi 



DlCOTYLID^ (=TaGASSUID^). 



X 



Desmathyus pinensis Matthew 

 Desmathyus sp 



Oreodontid^ (=Agriochcerid^). 



X 











X 















X 



X 













X 









X 









X 









X 















X 













X 











X 











X 











X 







X 









X 











X 





? 









X 



X 











X 











X 











X 





Merycochoerus proprius Leidy a. 

 Merycochoerus rusticus Leidy b . 



Merycochoerus sp 



Merychyus arenarum Cope 



Merychyus leptorhynchus Cope. 

 Merychyus minimus Peterson . . 

 Merychyus sp 



Mesoreodon chelonyx Scott . 

 Mesoreodon inte r m e d i u s 



Scott 



Mesoreodon megalodon Pe- 

 terson 



Mesoreodon ? latidens Doug- 

 lass 



Eporeodon sp. div 



Promerycochoerus carrikeri 



Peterson 



Promerycochoerus vantas- 



selensis Peterson 



Promerycochoerus sp. div . . . 

 Promerycochoerus hatcheri 



Douglass 



Promerycochoerus grandis 



Douglass 



Promerycochoerus hollandi 



Douglass 



Merycoides cursor Douglass. 

 Pheiiacocoelus typus Peter- 

 son 



" Merychyus elegans Leidy "c 

 '"Merychyus" harrisonensis 



I'eterson 



Leptauchenia sp 



Leptauchenia decora Leidy.. 

 Leptauchenia major Leidy. . 

 Leptauchenia nitida Leidy.. 



a ■' Headwaters ot Niobrara River, near Fort Laramie." 

 & Sweetwater River, Wyoming. 



(•Specific reference probably erroneous, generic reference of this and the following species doubtful. 

 The typical Merychyus is from the upper Miocene, the skull structure in the middle Miocene species is 

 considerably more spexjialized than m any from the lower Miocene and although unknown in the upper 

 Miocene species is presumably still more" specialized. The species from this early phase of the lower 

 Miocene have in general more brachydont molars, and it may prove necessary to separate them gener^ 

 ically. 



56092— Bull. 361—09 8 



