314 R- M. STRONG. 



B cf 



producing gametes B, c? all B 9 



W <? 



W, w cf 



result Blond males. Blond females. 



B cf B (9) B 9 B (c?) 



and also white females. 



B c? (W 9) W 9 W (cf) 



(See Table V. of this paper.) 



Still another mating combination is necessary to express the 

 conditions which may be expected when FI blond ring-dove 

 hybrids are mated inter se for the production of F 2 offspring. 

 5. Blond FI hybrid male X Blond FI hybrid female. 



composition B <f (W 9 ) B d" (W 9 ) 



B tf 



producing gametes B, cf B 9 



Wo* W 9 



W fw cT 



FZ Blond males. Blond females. 



B <? B (9) B 9 B 



and also and also 



B c? (W 9) B 9 (W 



White males. White females. 



W cT W (9) W 9 W (c?) 



(See Table III. of this paper.) 



From the two matings of this sort made, only one, out of the 

 eleven F 2 offspring obtained, was white, whereas the expectation 

 would be one out of four. However, the number of Fa off- 

 spring was too small to make a critical test and this result is not 

 especially significant. 



It will be observed that white hybrids crossed back on white 

 stock and white hybrids crossed inter se (see Tables XI. and 

 XVII.) gave white offspring, and males appeared as is to be 

 expected. The white hybrids are so-called extracted recessives. 

 Other results were also obtained some of which have been 

 mentioned on pp. 299-300 of this paper. In Table XXL, the 

 following records may be found : 



1. The number of broods in a season. 



2. The number of eggs in a brood. 



