296 THE OSTEOLOGY OF ELOTHERIUM.- 
Measurements. 
Fifth thorecic, height of neural spine. ..-.....-ecesecseeeeeegeceeteceaeeetscecersceseesensessecssescreenesses esi 
First lumbar, IGG MoosocsosconesanscosoracznencoABAS.EeESENNCERADNa HoDOUDBONNE> sonSECOOOBDOONDOSEEEDEEODODDSEOSOD .050 
SIDR REM ORNR, NE Ixa (EO jccocsocsoxdc000c0s03 29000000 90009n200299R00 D9Sdos09NDC0N9r joNHSaDEDGEgHDODOCHONBeOUE9INSIcGGN 048 
Sixth lumbar, breadth across tramsverse PYOCESSES.. .+--.+02cseceecesecs ete ecn sec seeeceseeeeseceserseees 176 
fSHYoTUITAS, IETDVR A Blo ccpcqoa0oomcoodocooan00se0cbon.cdoooboSdoAaSant non HDSEdoReOydOBDUDSEDCHaLCaSDOGe gaqNOKOOTaCeUAEADODOOdES c 098 
Furstisacrals-waidthoots cent iimissceccsesccsscasc ccssclscGarecivencssrestincsn apices stirasleetns cascelomeensicecensne .068 
Second sacral, width of centrum..... 
ANTEETTOR CAC, HET 29000 cosG0000Kc0 000 cbnan00009NqS00;300 p>noNIOoASHoDOnGNOAOHAEDOCIGHUHDSRDOIHCKOGBARHOEO 3 032 
Wicca Gamal, WER ccopsscoaccoonnnponannnoanoscoonocH.CHDaNNSAN}Guo9qo4 AHo.oAHonDOoHOSOnUONDONEY HoBooDNNAHOOET .063 
VY. THe Riss and STERNUM. 
The ribs of Elotherium are decidedly smaller and lighter and indicate a less capacious 
thorax than we should expect to find in such a large animal, a fact which adds to the 
apparent height of the skeleton, because of the long interval between the thorax and the 
ground. 
The first rib is short, subeylindrical proximally, but broadening considerably at the 
distal end; it has only a slight lateral curvature, appearing nearly straight when viewed 
from the front, but it arches moderately backward. The head is large and compressed, 
and is separated by a deep and narrow notch from the yery large and conspicuous 
tubercle, which is also compressed laterally. The ribs increase gradually in length up to 
the seventh or eighth of the series, and the posterior five, though successively shortening, 
retain a considerable relative length throughout. The first five or six ribs are laterally 
compressed and of moderate breadth, but the posterior part of the thorax is composed of 
very slender and subcylindrical ribs, very different from those which we find in most 
ungulates, except in the more primitive groups. The tubercle reaches its maximum of 
size and prominence on the third rib, behind which it gradually diminishes in size and 
becomes more and more widely separated from the head, and more sessile in position. 
On the twelfth and thirteenth pairs the tubercles are absent, corresponding to the lack of 
transverse processes on the twelfth and thirteenth thoracic vertebre. 
In Hippopotamus the ribs are relatively yery much longer, broader and heayier than 
those of Mlotherium, and grow broader toward the hinder end of the thorax, where the 
great bony slabs are in the sharpest possible contrast to the slender and subcylindrical 
rods of the extinct genus. In Sus the ribs are more like those of Hlotheriwm, but they 
have not such a regular and symmetrical curvature as in the latter. 
The sternum of Elotherium is a yery remarkable structure, and although it is of 
distinctly suilline type, it is, nevertheless, not altogether like the sternum of any known 
genus, recent or fossil. The presternum, or manubrium, forms a very large, thin, com- 
pressed and keel-shaped plate, which is especially remarkable for its great vertical depth, 
