TJ-:iiTIAliT VEETEBRATA OF TJIE FAYIjM. 
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backwards as in the ])vesent specimen ; moreover, as in the Elephant, the supra- 
scapular border is sharply bent above the origin of the spine, the portion in front 
making an angle of 65 degrees with that behind. The coracoid process is also quite 
dissimilar, while the s])ine inclines forwards rather than backwards and the prescap\ilar 
fossa is smaller. 
The humerus (text-fig. 16) differs very considerably both from that of Elephas 
and also from that of the Dinocerata. Its most striking general characteristic is 
the great antero-posterior compression of its shaft and distal end. The head (A.) 
is large and much more convex antero-posteriorly than from within outwards, so that 
it almost forms part of a cylinder. The head is most prominent posteriorly. The 
inner (lesser) tuberosity [l.t.) is small and its inner face flattened. The outer (greater) 
tuberosity {(J.t.) is large and forms a very prominent crest projecting considerably in 
front, but is not continued down the face of the shaft as a Avell-marked ridge, 
such as occurs in TJmtatherium, nor is it so massive as in Elephas. The bicipital 
groove [h.g.) is broad and not very distinct. Beneath it the shaft is strongly 
compressed from before backwards, and about the middle of its length it bears 
on its outer border a prominence [d.) formed by the great development of the deltoid 
crest for a short distance. From this prominence a short ridge runs obliquely across 
to about the middle of the shaft. The coronoid fossa [c.f.) is very shallow ; it is 
bordered internally by a broad rounded ridge running up towards the lower end 
of the oblique deltoid ridge above mentioned. The outer border is the inner edge 
of the prominent supinator ridge (s.r.), which, though much less developed than in 
Elephas, is much more so than in Uinfatherium. The outer condyle {o.c.) is large, 
but does not project far posteriorly ; the inner condyle {i.c.) also is very large, and is 
produced backwards into a proniiiieut projecting flange. The olecranon fossa io.f.) 
is broad and shallow, and the surface of the whole shaft above it is strongly concave 
from side to side, owing to the backward projection of the condyles. 
The trochlear surface for articulation with the bones of the forearm is divided by 
a shallow depression into an outer and less convex portion [tr.o.) articulating with 
the radius and ulna, and an inner more convex portion [tr.i.) articulating almost 
entirely with the ulna, the inner surface of the radius being very small (sec radius). 
The bones of the forearm are separate (text-fig. 19, p. 40); in their proportions 
they are short and stout, and the ulna is very much larger than the radius, as in the 
Proboscidea. In their general form these bones approach very nearly to those of 
Elephas, and differ widely from those of the Dinocerata. Fortunately, in one 
instance at least, an ulna and part of a radius were found associated with undoubted 
Arsinoitherium remains, with no intermingling of Ealaeomasfodon bones, in such a 
way as to leave no doubt as to the correctness of their reference to the present 
genus. Moreover, the size and massiveness of some specimens, as well as the large 
number found, point in the same direction. 
