70 



much more prominently developed in Antrodemus than in Ceratosaurus. It pro- 

 trudes conspicuously and comes to an irregular, blunt edge. Continuing downward 

 from this crest there is a decided angulation, which defines a narrow external flat- 

 •tening of the shaft, marking the surface for the contact of the fibula. 



J B C 



Fig. 48.— Left tibia, fibula, astragalus, and calcaneum of Antrodemus valens Leidy. No. 4734, U.S.N.M" 

 \ nat. size. A, front; B, outer; and C, back views, as, astragalus; ca, calcaneum;/, fibula; t, tibia. 



Dis tally, the anterior face of the tibia is transversely concave in its contact 

 with the ascending process of the astragalus, becoming flat where it articulates 

 with the fibula and calcaneum. The breadth of the distal end of the tibia in 

 Antrodemus, as in Gorgosaurus aud Dryptosaurus, is equal to the combined breadths 

 of the astragalus and calcaneum. 



