20 
Fig. 8. Proximal half of humerus, anconal or outer side, Alca impennis. 
Fig. 9. Distal half of humerus, anconal side, Alca impennis. 
Fig. 9'. Outline of section of shaft and medullary cavity of Alca impennis. 
Fig. 10. 
Fig. 11. 
Fig. 12. 
Fig. 13. 
Fig. 14. 
Distal end of shaft and medullary cavity of Alcea impennis. 
Front view of left femur, Alca wmpennis. 
Front view of left tibia and fibula, Alca impennis. 
Front view of right metatarsus, Alca impennis. 
Under surface of the sternum of Uria Grylle. 
(All the figures of Plate II. are of the natural size.) 
