THE PEDIGREE OF BIRDS 



351 



Fig. 51. — Skeleton of a Pterodactyl. ST., breastbone; t., tail: 

 FF., terminal flap ; w., wing ; d;, greatly elongated outermost finger ; 

 MC, metacarpals ; RU., radius and ulna ; H., humerus ; sc, scapula ; 

 c, coracoid ; p., pelvic girdle ; F., femur ; tf., fibia and fibula ; A., ankle 

 bones. The a. on the wing is an extra bone arising from the wrist. 



