152 



DR. R. BROOM ON THE 



articular surface for the tibia. It articulates with the fibulare, 

 the tibiale, and the fourth tarsal. The tibiale is relatively small, 

 and is wedged in between the intermedium and the first, second, 

 and third tarsalia. Though the tibia does not articulate with 

 it in most positions of the foot, it seems probable that it does 

 when the front is turned inward, as is manifestly possible. The 

 three first distal tarsals are all small but well ossified. The 

 fourth is very large ; its relations will be seen in the figure 

 given. The fifth tarsal is moderately large and fiat ; it 

 articulates with the fourth tarsal by a suture which allows very 

 little movement between the two. 



Text-figure 20. 



Text-fig. 19.— Left tarsus and metatarsus of Youngina capensis Broom *, as pre- 

 served. The foot has the plantar surface displayed, and the metatarsals 

 are somewhat distorted. Twice nat. size. 



Text-fig'. 20. — Right tarsus and metatarsus of Youngina capensis Broom, viewed 

 from the dorsal side, with the metatarsus restored in position. The 

 tibiale, first, second, third, and fourth tarsals of the right side are pre- 

 served in position, and have their dorsal aspects displayed. The fibulare 

 and part of the intermedium of the left side have had their dorsal surfaces 

 exposed and are added to the drawing reversed. 



* A Permian two-arched reptile of the order Eosuchia. 



The metatarsals are long, slender, and moderately straight 

 bones. The fifth metatarsal, which we should have expected to 

 be of the Sphenodon hooked type in this undoubted two-arched 

 reptile, is a long slender bone, nearly as long as the fourth meta- 

 tarsal, and it shows no trace of the peculiar hooking. The upper 

 end is expanded, and the outer process probably was attached to 

 the fibulare by a ligament. 



The remarkable points in the foot of Youngina are this 

 primitive generalized fifth metatarsal, and the fact that the tarsus 



