*M ORGANS OF SUPPORT, 



of the meta-carpal bone. When in a state of rest the hand 

 of the bird is folded along the exterior edge of the ulna, and 

 the large primary feathers are thus extended along the sides 

 of the trunk to the tail. These fingers appear to be the 

 analogues of the three middle fingers of the human hand, 

 and there is sometimes a single phalanx covered with a spur 

 on the radial side of these three fingers of the hand of the 

 bird. 



The bones of the pelvis, though anchylosed into a single 

 piece, consist of the ordinary three elements on each side, 

 as seen in that of the wild swan, (Fig. 51.) The two iliac 

 bones (a,) still extend forwards and backwards from the 

 cotyloid cavity along the sides of the sacrum, as in the 

 saurian reptiles ; and, as they are anchylosed to that bone, 

 the sacro-iliac articulation is here of great extent and secu- 

 rity. The iliac bones anchylose behind with the two ischia 

 (b,) and the sacro-sciatic 

 notch of mammalia is FIG - 



converted into a fora- 

 men (/,) but in the os- 

 trich it is a notch open 

 behind, as in most quad- 

 rupeds. The ossa ischii 

 are anchylosed at the 

 cotyloid cavity (/,) with the pubic bones (c,) and the three 

 pelvic bones enter into the composition of that cavity for 

 the head of the femur, as in other classes. The pelvic 

 bones are lengthened backwards, and taper downwards thin 

 and elastic to the anterior part of the pubis, where the two 

 pubic bones (d, d,) are separate and free at the symphysis, 

 excepting in the ostrich, where they are united by sychon- 

 drosis, as in mammalia. The obturator foramen (i,) has 

 here a long and narrow form, corresponding with the length- 

 ened form of all the bones of the pelvis. The pubic bones 

 are here free and elastic at their anterior terminations (d, d,) 

 that they may be susceptible of the necessary dilation, when 

 the large, brittle, and inflexible eggs are passing out through 

 the cloaca, and also to afford the necessary support to the 

 contents of the pelvis. The cotyloid cavities (Fig. 51./ 5 ) 

 are generally complete foramina, without an interior osseous 

 septum, and they are placed far forwards upon the pelvis, 



