Hind Limb of Fowl. 



109 



reality composed of three separate elements. The long process 

 and nearly one half of the rounded area is one element, the 

 ilium. The ventral part of the rounded area is cartilaginous, 

 and represents the pubis, while the remainder is the ischium. 

 It will be observed that the three bones take a share in the 

 formation of the acetabular cavity, in which is articulated the 

 femur. 



The Bird's pelvis is strikingly unlike that of the frog, and 

 yet the same elements can be traced in it. The whole pelvic 

 arch seems to consist of one large bone; but embryology 



Fig. so.— Pelvis of Chick. (From 

 Gadow, in Newton's " Dic- 

 tionary of Birds.") 



Fig. si.— Pelvis of adult Bird. (From Gadow, 

 in Newton's ** Dictionary of Birds.") 



ACf acetabulum; Pr.p, prepubic process: 

 F.is^ ischial foramen. 



shows that it is composed of a right and a left half, and that 

 each of these, again, is made up of three separate elements. 

 The greater part of each of the two innominates, as each half is 

 called, is made by the substantial ilitim which abuts upon the 

 sacral vertebrae. Running backwards, parallel with the ilium, is a 

 bone not quite so strong, the ischium. This is separated from the 

 ilium in the middle by a large foramen, the ilio-sciatic foramen. 

 Parallel with this, again, is a slender bone, the pubis, which is 

 nearly quite separate from it. All three bones join to form 

 the acetabular cavity, and in front of this the pubis gives off a 

 small forwardly directed process, ^e. prepubic process. 



In the Rabbit are the same three bones, which again share 

 in the formation of the acetabular cavity ; or, to speak more 

 accurately, the part of the apparent pubis within the acetabulum 

 ossifies separately as a small cotyloid bone. The two pubes 



