HOLLAND AND PETERSON: OSTEOLOGY OF THE CHALICOTHEROIDEA. 363 
In Macrotherium the patella apparently has a smaller vertical diameter than 
in Moropus. 
MEASUREMENTS OF PATELLA. 
No. 2193 Y.M. No. 1706 No. 1701, 
(M. elatus), (M. elatus), sp.(?), 
type, mm. mm. mm. 
Weereui@all Ciena Gide ea ere brs BORNE Od CBI e A ran oe mea ee acing Beet 114 115 70 
Eran SVeLSe kGLAMELC Eee aa er Geieks ciate ees ora ahalaraictsrencces Ghateiaeraton 84 82 G55 
Antero-posterior diameter... 2). ..05-.22+--ese ere ce recess 64 80 41 
The Tibia. 
(Plate LX XI.) 
The relative length of the tibia in Moropus is greater than in Titanotherium, 
being approximately four-fifths the length of the femur. The head is well ex- 
panded laterally, and has broad articular facets for the femur, which are separated 
by a prominent bifid spine. The cnemial crest is heavy, evenly rounded from side 
to side, and extends well down on the shaft. On the fibular angle immediately 
below the head is a slight rugosity, the attachment for the fibula. Below this 
point the transverse diameter of the shaft decreases rapidly, but the interosseous 
border continues as a rather sharp ridge downward to the distal end, imparting 
to the whole length of the shaft a subtriangular outline in cross-section, a feature 
less marked in Titanotherium, with which this bone has been compared, but similar 
to what may be observed in some of the early rhinoceroses, e. g., Trigonias. The 
distal end of the bone in its details recalls some of the features of the same element 
in the skeleton of Titanotherium, including the broad lip-like posterior malleolus, 
which in some individuals touches the caleaneum on extreme flexure. 
The tibia of Macrotherium, as figured by Blainville, and described and figured 
by Depéret, is very massive and short in comparison with that of Moropus. The 
head is relatively broader in Macrotherium, and there is therefore a more rapid 
decrease in the diameter of the shaft downward toward the middle of the bone 
than in Moropus, but distally the bone in Macrotherium appears to rapidly expand 
laterally, and to be broader than in the American genus. 
MEASUREMENTS OF TIBIA. 
No. 1704 No. 1701 No. 1424 
(M. elatus), (M. petersoni), (M. hollandit), 
mm. mm. mm. 
Greaitestplem ort vue ewuea areteegs Metts as cise 5 8's ela iejalee a a) 8c 512 353 380% 
Antero-posterior diameter of head..................000000- 150 80 are 
Transverse diameter of head............-.-.:ceeeeeceeeeees 168 105 118% 
Transverse diameter of distal end...................0..0005: 126 81 86% 
Antero-posterior diameter of distalend...................... 85 60 5685 
65 Approximate. 
