146 TEETIAEY VERTEBEATA OF THE EATtTM. 



this respect also it approximates to a humerus of Mastodon with which it has been 

 compared. The olecranon fossa {o.f.) is just as in Mephas, and the distal view of 

 the lower end of the humerus is almost precisely like that of a humerus of Elephas 

 meridionalis figured by Adams (' British Fossil Elephants,' pi. xvi. fig. 3). 



Hind Limb. — In the same locality was found a portion of a right os innominatum 

 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 

 Proboscidea, while, on the other hand, it is very unlike what is seen in the pelvis of 

 Arsinoitherium, 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 vrider and the pit for the Ugamentum teres is deeper. 

 The ischium is much more flattened and thinner than in Elephas and its postero- 

 superior 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 notch 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 does the pelvis of Elephas. 



A femur (PL XVI. flgs. 8, 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 Ugamentum teres (not shown in figure) in the middle of its 

 posterior half. The neck, which is directed obliquely upwards, is greatly compressed 

 from before backwards. The head {h.) rises less above the 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 dis tally on the flat posterior surface of the upper half of the shaft. In its 

 middle portion the hinder face of the shaft is convex and is produced 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 Blainville 

 (' Osteographie,' Atlas, vol. v. pi. xiii., Elephas) this ridge is well developed, but is 

 rather lower down the shaft than in Palceomastodon. At the distal end of the bone 



