IlG 
TERTIAIiY VEUTEBRATA OF THE FATCM. 
tliis respect also it ai)proxiitiates to a humerus of Mastodon with which it has been 
compared. The olecranon fossa (o./*.) is just as in Mephas, and the distal view of 
the lower end of tlie humerus is almost precisely like that of a humerus of Elephas 
meridionalis figured by Adams (‘ llritish Fossil Elejdiants,’ pi. xvi. fig. 3). 
Hind Limb. — Tn the same locality was found a portion of a right os innominatuni 
consisting of the acetabulum and the acetabular ends of the pelvic bones. This 
specimen differs in no important respect from the same region of the pelvis of the later 
Froboscidea, while, on the other hand, it is very unlike what is seen in the pelvis of 
ylrsinoitherium, the only other animal with which confusion would be likely. The very 
large acetabulum is perhaps a little more circular in outline than in Elephas, and at the 
same time the cotylar notch is wider and the pit for the ligamentinn teres is deeper. 
'The ischium is much more flattened and thinner than in Elephas and its postero- 
su])erior border forms a prominent crest-like ridge. The pubis is like that of Elephas. 
The upper end of the obturator foramen is like that of the African Elephant and is not, 
as in the Indian Elephant and the Mammoth, marked off into a sort of notch by a 
projecting point of bone. This specimen differs from the pelvis of Arsinoitherium in 
the following points : — (1) the acetabulum is nearly circular in outline, in Arsinoitherium 
it is oval ; (2) the cotylar notcli is much broader and the pit for the ligament larger 
and deeper; (3) the obturator foramen seems to have been relatively much larger; 
(4) the ischium is broader, thinner, and flatter. In short, it may be said that this 
specimen differs from the pelvis of Arsinoitherium in almost exactly the same respects 
as docs the pelvis of Elephas. 
A femur (El. XVI. figs. 3, 3 a) from the same locality is the only specimen of that 
bone in the collections of Cairo and London that is definitely Proboscidean in 
character and can be referred to Palceomastodon — a circumstance which still further 
emphasises the extraordinary rarity of bones of the skeleton of that animal. The 
head is nearly hemispherical ; it rises considerably above the great trochanter and 
bears a deep pit for the ligament um teres (not shown in figure) in the middle of its 
jmsterior half. The neck, which is directed obliquely upwards, is greatly compressed 
from before backwards. The head (Ji.) rises less above tlie great trochanter than 
in E. africanus, but more than in E. maximus. The great trochanter {g.t.) is 
developed to about the same extent as in the femur of Mastodon ; the smaller is 
represented by a slight ridge. The digital fossa is merely a shallow concavity, dying 
away distally on the flat posterior surface of the u])])er half of the shaft. In its 
middle portion the hinder face of the shaft is convex and is ])roduccd outwards 
into a prominent ridge {t.t.), which seems to represent the third trochanter ; this is 
also developed to some extent in the Mammoth femur, but scarcely at all in the 
recent Elephants. In a femur of Tetrabelodon angustidens figured by de Plainville 
(‘ Osteographie,’ Atlas, vol. v. pi. xiii., Elephas) this ridge is well developed, but is 
rather lower down the shaft than in Ealwomastodon. At the distal end of the bone 
