388 EXTINCT MAMMALIA OF NORTH AMERICA. 



ELOTHERIUM. 



Elotheriiim Mortoni. 



See page 175, PI. XVI. 

 Archaotherhim Mortoni, Leidy : Proc. Ac. Nat. Sc. 18.50, 90 ; Owen's Rep. Gcol. Surv. Wise, &c. 



1852, 558 ; Anc. Fauna Neb. 1853, 57, PI. VIII, IX, X, Figs. 1—7. Bronn : Leth. Geog. 



1856, 905. 

 Ardodon, Leidy : Proc. Ac. Nat. Sc. 1851, 278. 

 Archaotherium {Entelodon) Mortoni, Leidy: Owen's Rep. Geol. Surv. Wisc.&c. 1852, Ref. to Tab. 



X, Figs. 1—3, XI, 1, XIII, 1, 2. 

 Archceotherimn rohiistum, Leidy : Owen's Rep. etc. 572 ; Auc. Fauna Neb. 1853, 122, PI. X, Figs. 



8—13. Bronn : Leth. Geog. 1856, 905. 

 Rhinoceros americanus, Leidy : Proc. Ac. Nat. Sc. 1852, 2. 

 Arehceofherium (Entelodon) robustum, Leidy : Anc. Fauna Neb. 1853, 66. 

 Entelodon Mortoni, Leidy: Proc. Ac. Nat. Sc. 1853, 392; 1854, 157 ; 1857, 175. 

 Archceotherimn, Greene : Proc. Ac. Nat. Sc. 1853, 292. 

 Elotherium Mortoni, Leidy : Proc. Ac. Nat. Sc. 1857, 175. 



Mauvaises Terres of Dakota. Miocene. 



Elotherium ingens. 



See page 192, PL XXVII, Figs. 8—11. 



Entelodon ingens, Leidy : Proc. Ac. Nat. Sc. 1856, 164 ; 1857, 89. 

 Elotherium ingens, Ibidem, 1857, 175. 



Mauvaises Terres of Dakota. Miocene. 



Elotherium Lieidyanum. 



Marsli : 



Cope : Cook's Geol. N. Jersey 1868, 740. ' ^ 



The largest American species, from Squankum, Monmouth Co., N. J. Most proba- 

 bly of miocene age. 



Elotherium superbum. 



Leidy : Proc. Ac. Nat. Sc. 1868, 177. 



A species indicated by an incisor tooth, obtained by Prof. Whitney from Douglas 

 Flat, Calaveras Co., California. It was derived from a stratum of the same age as 

 that from which a lower jaw of Rhinoceros hesperius was taken. The tooth appears 

 to me to be the right upper lateral incisor of a species o^ Elotherium, perhaps the same 

 as E. ingens of the Mauvaises Terres of White River, Dakota, though it would appear 

 to belong to a larger individual than the remains referred to the latter, if not to a yet 

 larger species. The crown of the tooth is conical, compressed from within outwardly, 

 and subacute laterally. The apex is rounded ; the base somewhat expanded, and at 

 its fore part produced in a short embracing ridge. The fang is conical and curved. 

 The measurements of the specimen are as follow : 



Length of tooth in straight line twenty-nine and a half lines ; length of crown 

 thirteen lines ; breadth nine lines ; thickness six and a half lines. 



