HOLLAND AND PETERSON: OSTEOLOGY OF THE CHALICOTHEROIDEA. 329 
MEASUREMENTS (No. 1604). 
Mm 
Length of fourteenth right rib. Measured in a straight line............... 460 
ID (AME FETLO lM CAC Cerrina te 7 Sia. Toacg macea caiman oar Mi MYR DUR wt erp nae, Lt Dil 
Greatest diameter of shaft near the middle.........................2.... 22 
Greatestidiameter/ of shaft near endl). 25.5 225..0.-000..5.-2-+5- ences seen 25 
The Fifteenth Rib. 
The fifteenth rib is quite short and reduced to a fine point at its extremity. 
In transverse section it is somewhat oblong from the middle to the end. At its 
upper extremity it is subtriangular in section below the angle, which is indicated 
merely as a slight tuberosity succeeding the tubercular face. The capitulum and 
tuberculum in this rib are united, the capitular surface looking forward and inward 
in relation to the vertebre, and the tubercular surface looking inward and backward. 
Measurements M. elatus (No. 1604). 
Mm 
Length of fifteenth rib. Measured in a straight line...................... 330 
DIATE CETAO lane a Gl Alearesty ate t eta BAI etic var, Wee eae ORI Ree Sy ee lt cased Ait ued oy 27 
Greatest diameter of shaft near the middle....................0..00-005- 24 
Greatest diameter of shaft near the end................0.. 00 eeceeeeeeee 13 
THE STERNUM. 
But few remains of the sternum have been found in our quarries. The only 
portion of this element thus far detected in the material which has been excavated 
and freed from the matrix is a manubrium (No. 1763) pertaining to an apparently 
adult specimen of Moropus elatus (?) somewhat smaller in size than No. 1604. This 
manubrium has been used as the model in preparing the sternum utilized in the 
mounted skeleton. The accompanying illustration (Fig. 75) gives the outline 
of this specimen. 
The manubrium is laterally compressed as in other perissodactyls, its height 
being greater than its width. This compression is most noticeable on the under 
side, the lower portion of the bone being thin and sharp. The anterior end extends 
well in front of the surfaces for the attachment of the ribs. Back of the attach- 
ment for the ribs the bone is triangular in cross-section, with the superior and 
lateral surfaces subequal in diameter, while inferiorly there is a sharp, but rounded 
border or keel. ‘The posterior end is enlarged to accommodate the mesosternum, 
and the second pair of ribs. 
