K. TOYAMA 371 



matured gave, without any exception, normal ^3 batches, the number 

 being 461. Their posterity only gave one batch of grey eggs in four 

 successive generations during which they produced 1042 batches. Thus 

 we may safely say that some of the normal-egged form which appeared 

 in the F^ are homozygous from their first appearance. 



Descendants of the F„ grey batches derived from the same summer 

 brood, on the contrary, produced the antagonistic normal-coloured 

 batches in F^ (the spring of 1910). Of five matings reared, four 

 yielded grey, normal, and B-grey F^ batches, while one gave grey and 

 B-grey, no normal batches. In the former, we found 20 normal, 

 34 grey, and 5 B-grey batches, and in the latter 6 greys and 3 

 B-greys. 



In the summer of 1910 we again reared nine grey batches, one 

 of which was derived from a mating which did not produce any normal 

 eggs in the last generation. Each of them yielded three kinds of 

 Ft batches, normal, grey, and B-grey, except three matings (Nos. 2. 4. 1 ; 

 2. 8. 6 ; 2. 8. 4) which gave only grey and B-grey batches. The total 

 number of F^ batches obtained in the former matings was 78 (26'5 7o) 

 normals, 126 greys, and 90 B-greys, and in the latter 51 greys and 

 30 B-greys. Two B-grey F^ batches which were reared in the same 

 season gave only four Ft batches, one being grey and three B-greys, no 

 normal batches. 



The autumn (1910) brood derived from the summer grey brood, 

 which laid only grey and B-grey batches, gave F^ batches, in which we 

 again found normal batches, but their proportion became gradually 

 lessened as the figures show, namely, of five matings derived from the 

 grey mating No. 6 which did not produce any normal batches in the 

 summer, two gave 28 normals, 71 greys, 39 B-greys, Fr^ batches, the 

 remainder 68 greys and 55 B-greys. Of seven derived from No. 1 

 mating, which as in the former gave no normals in the summer, five 

 gave three kinds of F^ batches (15 normals, 52 greys and 27 B-greys) 

 and two no normal batches (12 greys, 18 B-greys). In the former 

 lineage, therefore, the proportion of normal batches is 20 7o and in the 

 latter 14-4 7„. 



In the spring of 1911, we again reared nine grey batches derived 

 from the brood which produced no normal batches in the last generation. 

 They gave 103 F^, batches of eggs of which 49 were grey, 49 B-greys 

 and five a mixture of both kinds of batches. 



Ten batches of B-grey eggs derived from the same parents as above 

 matings were reared, but all of them died before attaining maturity. 



