44 THE STRUCTURE AND LIFE OF BIRDS chap. 



wing is very different from the pterodactyl's. To the 

 support of the latter only one finger, often called the 

 ulnar finger since it articulates with the postaxial side 



Fig. 17.— (1) Pterodactylus Spectabilis, from lithographic-stone, Bavaria. 



of the arm, contributes, and this one may be either No. 

 4 or No. 5. The settlement of the question depends 

 upon the nature of the small bone which can be seen 



