244 



CASE. 



[Vol. II. 



articular surfaces. The tibia shows on the anterior end the 

 deep groove which defines the cnemial crest. 



The tarsus of the left foot is preserved, but the bones are 

 somewhat displaced. There are eight bones. The most inter- 

 esting thing about the foot is the fact that 

 the proximal row is composed of two 

 greatly enlarged bones that can only be 

 astragalus and calcaneum ; the astragalus 

 is the larger, with strong articular faces 

 for the calcaneum, and for the first and 

 second tarsals of the distal row. The 

 calcaneum is a large, round, and very thin 

 bone that is preserved in the natural posi- 

 tion ; it articulates with tibia in common 

 with the astragalus. The other bones of 

 the tarsus are out of position, but one 

 triangular-shaped bone lies over the astra- 

 galus and calcaneum ; this seems to be 

 the intermedium or, more likely, the cen- 

 trale (naviculare) ; the intermedium having 

 joined the tibiale to form the astragalus. 

 The five remaining bones : considered as belonging to the 

 distal row, and the largest has been placed as the fifth, the 

 fourth and fifth not having yet united to form the cuboid. 



There is a separate fragment of bone 

 that is so poorly preserved that it is 

 impossible to say whether it is a com- 

 plete bone or not ; if it is it may be 

 either a second centrale or the inter- 

 medium (Fig. 8). 



The discovery of the well-differen- 

 tiated astragalus and calcaneum throws 

 a new light on the position of the 

 Cotylosaiiria, for the proximal row of 

 the tarsus in Fareiasanrus, as figured 

 by Seeley, consists of a single bone ; 

 this difference must be considered as evidence in favor of the in- 

 dependence of Cope's order Cotylosanria from the Parciasa^iria. 



Fig. 7. 



Fig. 8. 



