INHERITANCE OF FECUNDITY IN DOMESTIC FOWL. 349 



5) have been repeatedly tested in the breeding pens in various 

 different combinations. The zero winter producing" females 

 have been fairly often bred, but the difficulties of getting chick- 

 ens hatched within the necessary time limits and in sufficient 

 number to get adult daughters for fecundity work have been 

 too great for the available resources. Of the nine possible types 

 of males six have been tested in various combinations. 



It may fairly be said, I think,' that in its range, its quality and 

 its amount, the evidence from the pure Barred Rock matings, as 

 set forth in the preceding sections, is sufficient alone to demon- 

 strate the Mendelian inheritance of fecinidity in the breed of 

 fowls. If, however, the principles set forth above for Plymouth 

 Rocks are true, they ought to apply, in general at least, to other 

 breeds of fowls and to crosses, with, of course, possible limita- 

 tions and modifications in particular instances. It is desirable, 

 therefore, to examine the results regarding the inheritance of 

 fecundity in other breeds and crosses. This we may proceed to 

 do. 



Cornish Indian Game matings 



The strain of Cornish Indian Game fowls used in these expe- 

 riments is characterized, as has already been pointed out, by 

 very poor egg production. There is no evidence that any of 

 the individuals, either male or female, ever carry the second 

 fecundity factor Li. These birds therefore represent the ex- 

 treme condition in the way of low fecundity as compared with 

 the Barred Plymouth Rocks. 



The Cornish Indian Game is an old breed and if one may 

 judge from poultrymen's accounts, there certainly have existed 

 in the past, and probably exist now strains of birds belonging 

 to this breed which are fairly good layers. Such strains, which 

 are in marked contrast to the one here used, undoubtedly carry 

 in some combination, the second fecundity factor Z,?. There is 

 nothing extraordinary, or contradictory to the results of the 

 present paper, in such a fact (if it be a fact). Indeed it will 

 be shown, in a later section of this paper, how it bas been possi- 

 ble experimentally to form synthetically high laying Game hens, 

 i.e., to put the factor L". into their hereditary constitution (cf. 

 section on /^'- matins^s I. 



