No. 492] SOME AMERICAN CHALICOTHERES 



751 



Professor Osborn has pointed out INIeniscotherium from the 

 American Eocene (Wasatch) as a possible ancestor of tlie Chah- 

 cotherioidea/ It would seem that when better specimens of Moro- 

 pm distans^ve found in -lolm Day formation, it will become 

 necessary to separate, o-cnerieally, Moropti.s' c/atiis froin Moropus 

 distans. Chalicoiheviiini h/lohaiuni" Cope from the Oligocene 

 of the Swift Current ("reek in Canada, if correctly identified, is 

 of course a much earlier form than Moropus elatus from the Mio- 

 cene of Nebraska. The i-emains which Professor Scott reports 

 from Montana (Deep River) may ])erhaps represent a transitional 

 form between Chalicotheriiim h/Ii)hafiini and Moropus claim. 

 These appear to be the evidence wliich we ha\e of the j^resence of 

 the chalicotheres in the American Tertiary, '{'he little known 

 Spenococlus iiintrnsis Osborn from the Uinta i)eds- i)ears some 

 resemblance to the Chalicotherioidea as was pointed out by ( )sl)oni 

 (1. c. p. 102), but the specimen (the posterior porti(»n of the skull > 

 is too imperfect for accurate comparison. While MeniseotheiMuin 

 may not be a true ancestor of Moropus there are in the hitter rcv- 

 tahi affinities-'' to the former which are of much importance and 

 which point to the ancestral types of the stem of the Perissodactyla. 



