No. 492] 



SOME AMERICAN CHALICOTHERES 



745 



vertebrae well co-ossified, with high and backwardly sloping nenral 

 spines which are all co-ossified and increase in robustness from be- 

 fore backward. The neurapophysis of the first sacral is very heavy 

 and supports the greatest weight of the ilium, though the succeed- 

 ing three sacrals share in the support as there is a rugose attach- 

 ment for the ilium throughout the entire length of the sides of the 



A number of caudals of considerable length, found in the 

 quarry, may belong to Moropus but this is not fully determined 



In No. 1604, Car. Mus. Cat. Vert. Foss., the best preserved 

 skeleton of IMoropus, there are present fifteen ribs of the right and 

 fourteen of the left side; the first rib of the left side is lost. The 

 ribs are of moderate length, but robust, and the anterior ones are 

 expanded at the lower ends, indicating a heavy sternal attachment. 



Limbs 



Nos. 1G04; 1706; 1710; Carnegie :\Ius. Cat. ^ >rt. Foss. 



The structure of the fore and hind liinlvs of Moropus w as briefly 

 described in a former paper,' and 1 wish lien- ohIn to call attention 

 to a few of the more important fcatuics wliicli arc shown in the 

 splendidly preserved material in the Carnegie Museum. 



The Fore Limb. — The scapula of Moropus is quite large. It is 

 plainly of a perissodactyl type, anri resembles most closely that of 

 Aceratherium iridachjlum Osborn. As in the latter genus the spine 

 is prominent and overhangs the post-sca})ular fossa in a similar 

 manner. The humerus, radius, and ulna of Moro[)Us, as a whole, 

 are quite like these parts in the l^:uropean genera.^ I'he humerus 

 of Moropus has a hcaxy .h'hoi.l ridgcN which extends well down 

 on the shaft. The grcat<-r tiilx-ro.ity i- al-o .piite robu.st and the 

 bicipital groove is sinuic and niodcrati^ly drcj), ))ut quite broad. 

 The distal eiiil is nnich rxpand. d tran.\ *M-M'ly an.l suggests that of 



