EVOLUTION OF THE CHICK. 165 



Position of the Chick in the Egg. 



Reaumur observed, is towards the biggest end ; and 

 Dr. Prout adds, that it "is so situated in the egg-, 

 as, by its superior weight on one side, to assume 

 such a position that the beak shall be uppermost *." 

 It is surrounded by a thick strong membrane, which 

 retains it in the attitude just described, and is appa- 

 rently unfavourable to its requisite movements. But 

 closer inspection shows that all these circumstances 

 tend to facilitate rather than retard its operations on 

 the shell, which it must break before it can escape. 



The bill, indeed, though placed under the wing, as 

 in the case of a sleeping bird, is thrust so far as to 

 project beyond it towards the back, and the head, by 

 moving backwards and forwards alternately, causes 

 the bill to strike upon the shell, the action being 

 partly guided by the wing and the body. It is to be 

 * Phil. Trans, for 1822. 



