OSTEOLOGY OF AMERICAN PERMIAN VERTEBRATES 409 

 5 x.^.^..:.^ 6 



Fig. II. — Arribasaurus navajoicus Case: i, distal end of left humerus, ventral 

 side; 2, calcaneum and astragalus, from the front; 3, left carpus, from the front; 4, 

 left femur, dorsal side; 5, pubis; 6, right calcaneum and astragalus of young, from the 

 front; 7, spine of axis; 8, spine of dorsal vertebra; g, distal end of young humerus; 

 10, right immature humerus, dorsal side; 11, the same, ulnar side; 12, two dorsal 

 vertebrae, from the side; jj, distal end of tibia; j_/, distal end of fibula. All natural 

 size. 



