436 PEARL— SEX RATIO IN DOMESTIC FOWL. 



prenatal mortality is not differential in respect to sex, and that in 

 consequence the observed sex ratio at birth is substantially the same 

 as the initial zygotic sex ratio. 



V. Conclusion. 

 The purpose of this paper is to present data regarding the normal 

 sex ratio in the domestic fowl. The data involves something over 

 22,000 chicks. The normal variability in sex ratio is discussed. It 

 is hoped in a later paper to present a further analysis of the sub- 

 ject dealing with the influence of various internal and external fac- 

 tors upon the sex ratio. It was expected to include such discus- 

 sion in the present paper but for reasons explained at the beginning 

 of the paper this is not now possible. 



