THE ANATOMY OF A BIRD 



19 



single and remarkable exception of the South American Screamers 

 (Chauna, Palamedea), a group of birds occupying a rather isolated 

 position, and showing resemblances to a great many different groups. 



Pelvis. 



The hind limbs are attached to the vertebral column by means 

 of a considerable bony structure known as the pelvic girdle (fig. 13). 



FIG. 13 PELVIS AND HIND LIMB OF DIVER. 



c, d, ilium ; 63, ischium ; 64, pubis ; 65, femur ; 66, tibia ; 67, fibula; 

 68, tarsometatarsus ; i.-iv. digits with phalanges numbered. 



This mass of bone is in reality composed of three pairs of elements, 

 though they are in the adult strongly compacted together. The main 

 bone, which is firmly attached to the vertebral column, is the ilium ; 

 with this is almost completely fused the ischium ; the very slender 

 pubis is to a large extent free from these bones. The pelvis is in its 



