HOLLAND AND PETERSON: OSTEOLOGY OF THE CHALICOTHEROIDEA. 307 
The second lumbar vertebra is characterized by the backward and outward 
slope of the extremity of the mammillary process or metapophysis, which is more 
strongly marked in Moropus elatus than in Moropus peterson. ‘The articulating 
surfaces for the postzygapophyses of the first lumbar occupy more than half of 
Fic. 66. Second lumbar of M. elatus Fig. 67. Sheond lumbar of M. petersoni (No. 1708C). X32. 
(No. 1604). x4. 1, lateral view; 2, posterior view. 
the inner surface of the metapophysis measured vertically. The spine corre- 
sponds in general outline with the preceding vertebra, except that at its upper 
extremity it is not as strongly produced forward, and is relatively longer. The 
transverse processes in Moropus elatus are directed somewhat more backward than 
in Moropus petersoni, which they otherwise closely resemble in structure. The 
centrum is subtriangular in cross-section at its middle. 
MEASUREMENTS OF SECOND LUMBAR VERTEBRA.“ 
1604, 1703C, 1708, 1713, 1714D, 
mm. mm. mm. mm. mm. 
Greatest height from base of centrum to top of spine...............-..-- 248 186 sq Cal) 
Greatest transverse diameter measured across transverse processes........ 200 152 
Greatest antero-posterior diameter measured from front of prezygapophyses 
to back of postzygapophyses............... octal Rare a tee oe pee 125 96 eo lil) 82 
Length of centrum along floor of neural canal.......................--. 78 57 66 50 43 
Wenethyoteentrumialonganienionsuriacese sacs. © ae soe eee aes sia 61 50 51 40 85 
Vertical’ diameter of anterioriace of centrum... .//.......<++:2..+.+:5-+--- 64 47 61 52 40 
“1 Numbers in italics denote approximate measurements. 
