VI.J 



THE COMMON FROG. 



87 



which is adjoined to the sacrum. The pubis, in man, 

 meets its fellow of the opposite side in the middle line 

 in the front of the body. The two ischia (one to each 

 haunch-bone) support man's l^ody when in a sitting- 

 posture. 



The pelvis of man is often quoted as one of the 

 most peculiar and characteristic parts of his skeleton, 

 and its shape in him is very pecuhar. Nevertheless 

 the pelvis as it exists in frogs and toads is a far more 

 exceptional structure. It is so in the extraordinary 

 elongation, yet small vertebral attachment, of the 

 haunch-bones {ilia), as also in the fact that these bones 

 as well as the other pelvic elements {ischia and piibes) 

 are all closely applied to each other in the middle line 



^<$c 



Fig. 52. 



Fig. 53. 



Fig. 52. — Right side of Pelvis of Frog, il, ilium ; is, ischium ; p, pubis. The thiee 



bones meet at the upper margin of the acetabulum. 

 Fig. 53. — Dorsal view of pelvis of Frog, showing the narrow ends of the ilia for 



attachment to the backbone, and also the close approximation of the acetabula. 



of the body. Thus these elements form a bony disc, 

 and the two sockets {acetabula) destined, respectively, 

 for the heads of the two thigh-bones, come to be 



