AESINOITHEEIUM. 



55 



are the ectal (ec), which is the smaller and is convex from before backwards, 

 and the sustentacular (sus.), which is much larger, flat anteriorly and concave behind. 



? nau. ^^'^^ 



Text-fig. 32. 



2A 



?nav 



nau. 



Left calcaneum and astragalus of Arsinoitherium zitteli : 1 a, calcaneum from above ; 1 b, distal surface of 

 calcaneum ; 2 a, tibial surface of astragalus ; 2 B, anterior view of astragalus ; 2 c, distal surface 

 of astragalus. 



cub., facet for cuboid ; ec, ectal facet ; fib., fibular facet ; n., notch in hinder border of tibial surface • 

 new., navicular facet ; ms., sustentacular facet ; ? t., facet for tibiale ; t.c, tuber calcis ; tib., surface for 

 tibia. J nat. size. 



