CHAPTER VIII 



THE DEVELOPMENT FROM THE SIXTH DAY 

 TO THE TIME OF HATCHING 



The sixth and seventh days. It is during 

 this period that the distinctively avian charac- 

 teristics make their appearance. 



Up to this time there is nothing about 

 the embryo that would enable the inexperi- 

 enced eye to distinguish the chick embryo 

 from that of many other and quite different 

 animals ; and, in fact, it would be difficult, if 

 not impossible, for even an experienced eye 

 to distinguish the chick embryo, during the 

 very early stages, from other embryos at a 

 corresponding state of development. 



It is at this time that the nasal region be- 

 gins to lengthen, and the anterior and pos- 

 terior limbs begin to take on the form of 

 wings and legs (Fig. 72, B). 



The amnion does not now lie so close to 

 the embryo as during the earlier stages, and 

 in the enlarged amniotic cavity has collected 



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