OF WESTERN NORTH AMERICA. 



105 



MIDDLE OLIGOCENE. 



Brule (lower part) (White River group). 



Oreodon zone. 



1. Lower Brule, South Dakota and adjoining parts of Xel)raska and Wyoming. 



2. Cedar Creek, northeastern Colorado. 



3. Scattered exposures in southwestern Montana. 



1. 



MARSUPIALIA. 



DiDELPHYID.E. 



Peratherium fugax (Cope) 



Peratherium tricuspis (Cope) . . , 



Peratherimn huntii (Cope) 



Peratherium scalare (Cope'r 



Peratherium marginale (Cope) . 

 Peratherium alternans (Cope) . . 

 Peratherium pygmsemn (Seott;i 



CARXIVORA (CREO- 

 DONTA). 



H Y.EN'ODOXTID.E . 



Hyaenodon horridus Leidy 



Hyaenodon cruentus Leidy 



Hyaenodon crucians Leidy 



Hyaenodon paucidens O. "and W 



Hyaenodon leptocephalus S. and O . . 



"Hyaenodon mustelinus Scott 



Hyaenodon montanus Douglass 



CARXIVORA (FISSI- 

 PEDIA). 



Caxid^. 



Daphoenus vetus Leidy 



Daphoenus hartshomianus (Cope).. 



Daphoenus felinus Scott 



Daphoenus nebrascensis (Hatcher)a. 



Daphoenus inflatus (Hatcher) 



Cynodictis gregarius (Cope) 



Cynodictis lippincottianus (Cope)... 



MUSTELID.E. 



Bunaelurus lagophagus Cope. 

 ? Oligobunis sp , 



Felid-E. 



Dinictis felina Leidy 



Dinictis squalidens'(Cope) 



Dinictis paucidens Riggs 



Hoplophoneus prim«vus (Leidy) . . . 

 Hoplophoneus occidentalis (Leidy) . 

 Hoplophoneus oreodontis Cope. ~. . . 

 Hopl-ophoneus sp. (transitional to 

 Eusmilus) 



INSECTIVORA— Continued. 

 T.\lpii).t:. 



Domnina gradata Cope 



Domnina crassigenis Cope. 

 ? Geolabis rhynchaeus Cope . 



X 



RODENTIA. 



SCIURID.E. 



Prosciurus relictus Cope 



Castorid.e. 

 Eutypomys thomsoni Matthew. 



ISCHYROMYID.E. 



Ischyromys tj-pus Leidy 



Ischyrorays cristatus (Cope) 



GjTnnoptychus (=Adjidaumo) mi- 



nutus Cope 



Gymnoptychus ( = Adjidaumo) trilo- 



phus Cope 



MURID.E. 



Eumys elegans Leidy. . 



Leporid.e. 



Palaeolagus haydeni Leidy. 

 Palaeolagus turgidus Cope. 



PERISSODACTYLA. 



HYRACODONTID.E. 



Hyracodon nebrascensis Leidy.. 



Hyracodon arcidens Cope 



Hyracodon major S. and O 



AMYNODONTID.!:. 



Metamynodon planifrons S. and O.J 



PiHlNOCEROTID^E. 



Caenopiis (=Rubhyracodon) occi- 

 dentalis Leidy 



Caenopus (= Sub hyracodon) copei 



Osborn 



Caenopus ( = Subhyracodon) simpli- 



cidens Cope 



Leptaceratherium trigonodum (O. 



and W ) 



"Hyracodon" planiceps S. andO... 

 Anchisodon quadriplicatus Cope 



LOPHIODONTID-E. 



Colodon (=Mesotapirus) procuspi- I 



datus O. and AV | X 



Colodon (=Mesotapirus) dakotensis \ 



O. and W 



Colodon (=Mesotapirus) cingulatus 



Douglass 



Colodon (=Mesotapirus) longipes 



O. and W 



INSECTIVORA. 



ER1XACE1D.E. 



Proterix loomisl Matthew 



Leptictid^. 



Leptictis haydeni Leidy 



Ictops dakotensis Leidy 



Ictops bullatus Matthew 



Ictops porcinus (Leidy) 



Mesodectes caniculus Cope 



SORICID^. 



Protosorex crassus Scott 



a Mr. Hatcher regarded this and the following species as types of distinct genera. As all the distinc- 

 tive characters are fimctions either of the size of the species or the wear of the teeth they can hardly l.e 

 regarded as of generic importance. D. nebrascensis is in fact very closely related to D. felinus and 

 D. vetus, and D. inflatus to D. hartshomianus. 



