EEEMOPEZUS EOCyENUS. 
259 
approximation to this condition is seen in Stnithio, and still more in Rhea. The 
surface between the postcondylar processes is slightly concave, and above passes into 
the posterior surface of the shaft, which, like the articular end, is strongly compressed 
from before backwards. The lateral faces of the condyles bear deep pits for the 
attachment of ligaments (text-fig. 84 B). 
The posterior face of the shaft passes by a gentle slope into the sharp antero-internal 
border of the bone, which is continuous with the upper angle of the inner condyle, as 
in Casuarius and Bromceus. The anterior face of the shaft near its inner border is 
deeply channelled by the groove for the extensor tendons (text-fig. 84 A, e.g.) ; this 
groove is closed at its lower end by a strong ridge running upwards and outwards 
towards the lower border and forming a prominent rugose surface above the outer 
Text-fig. 84. 
Distal end of left tibio-tarsus of Eremopezus eoccenus (type specimen) : A, from front ; B, from outer side ; 
C, from behind. (From Proc. Zool. Soc.) 
a., angle between outer condyle and postcondylar surface ; e.g., extensor groove ; i.c., inner condyle ; 
O.C., outer condyle ; t., tubercle marking base of tendinous bridge. | nat. size. 
condyle. There is no extensor bridge, but a slight ridge along the inner side of the 
groove marks the insertion of a strong tendinous sling (t.). 
Compared with the tibio-tarsi of other Eatites this specimen appears to combine the 
characters of several of them. In the depth of the extensor groove it approximates to 
Rhea and JEpyornis. The oblique ridge which blocks the lower end of the groove 
occurs also in Struthio, though in this case the groove itself is much narrower. 
In A^pyornis, on the other hand, the ridge is wanting, and the groove runs nearly 
down to the condyles. The form of the outer condyle and its relations to the 
postcondylar process are similar to what is seen in Rhea, and to some extent also 
in Struthio. 
There seems to be no doubt that this fragment indicates the existence of a large 
Eatite bird in the Upper Eocene beds of Egypt, but much more material is necessary 
before its relationships can be determined satisfactorily. 
