1 86 



THE OSTEOLOGY OF THE REPTILES 



malian names astragalus and calcaneum and abandon the names 

 tibiale, fibulare, and intermedium for the reptilian tarsus. Of the 



Fig. 153. Limbs: A, Mesosaurus (Proganosauria). Modified from McGregor. Natural size, 

 B, Sauranodon (Protorosauria). Modified from Lortet. Three fourths natural size. 



centralia the most probable theory is that the fourth of the amphib- 

 ian tarsus has united with the astragalus, the third with the fourth 

 tarsale. The second is known to fuse with the astragalus in the 



