FIG. 53. Pelvic vertebrae of young Alligator. 



Fia. 54. Pelvic vertebrae of American Flamingo. 



FIG. 55. Pelvic vertebrae of Bald Eagle. In the reptile, where there is no need 

 for rigidity, only two typical pelvic vertebrae are joined together; in the birds 

 many dorsal and caudal vertebrae are joined with these to make a rigid frame 

 for flight and for bipedal locomotion. 76 



