172 



INHERITANCE, FERTILITY, AND SEX IN PIGEONS. 



We may here list the sex-relation of the 2 eggs of the clutch as it is displayed in 

 the records of the several matings and species dealt with in the present chapter.* 

 If A be allowed to represent "pairs of eggs" in which the first egg produced a male 

 and the second a female, and B the reverse, we then may read as follows : 



' These birds hatched from the first or last clutch of the season. 



It thus appears that from all of these "pure-bred" females, representing several 

 different species, the first eggs of the clutch more often produce males and the 

 second more often females. This has been noted in previous chapters to hold for the 

 species considered there. A further word concerning this general situation should 

 doubtless be added. 



From the time of Aristotle to the immediate present there have appeared state- 

 ments concerning a predominance or a lack of predominance of males from the first 

 egg and of females from the second egg of the pigeon's clutch. It is quite unnec- 

 essary to discuss at length any of these divergent reports. They have all been based 

 on a general statistical method, which is a wholly inadequate and useless method 

 for a study of the problem. It is clear from aU that has preceded in this volume that 

 the method that would be valuable must be an analytical one. The author has 

 laid the foundation, and fashioned much of the superstructure, of a proper analyt- 

 ical study of this point. He has shown that from the periods of the production of 



Table 172. 



>Only matings in which the female is "pure bred" (not hybrid) are tabulated. The proportion of males and 

 females from the 2 eggs of the clutch in other species, or in matings of some of the above species with still other forms, 

 has been considered in the several previous chapters; i.e., in connection with the fully tabulated records. — Editor. 



