•')() On Inheritance of Weif/ht in Poultrij 



Fn.iii iJiis mating wrrc rcari'd (i </(/ and 7 $$. The (i </(/ rangrd 

 h(jin 720 to 8(i0 grams, averaging 800, half being about the same size 

 as the father and half rather larger. Of the 7 ^ $ four were smaller 

 than (,heir mother while the other three were of about the same size or a 

 little larger. In other words there were nearly eijual numbers in l)oth 

 se.\es of regular bantams and (jf biids rather larger. The residts ai-e in 

 accord with the view that the father was a true bantam, and that the 

 mother was heterozygous for a factor which had the effect of increasing 

 the weight of a bantam by about 25 7o- 



These F^ results taken together suggest stnjngly tha,t size in poultry 

 depends upon definite factors, and that these factors segregate in 

 gametogenesis. More experimental data are required before we can 

 hope to determine the nature anci number of these factors, and we have 

 already designed some further experiments with this end in view. 

 Meanwhile we may give an account of some other data. \vi' havt' got 

 together in connection with the inheritance of size. 



i^i ,/ X Bantam. We mentioned above that two i*', ^ ^ ex Silver 

 Sebright x Gold Hamburgh were reared in 1910, but that owing to 

 the lack ol F^ $ $ we were unable to breed an F. generation in the 

 following year. One of these F, J ^^ was put to two Gold Sebright 

 hens in 191 1 (Pen 7, imi ) and from this mating 7 c/j" and 11 ? ? were 

 reared. Of the former 2 were bantams under 700 grams, while the 

 remaining 5 ranged from 800—900 up to 1100—1200. Of the pullets 

 6 were undei- 700 grams, 3 were of the usual F^ size and the remaining 

 2 were intermediates. From these birds two pens, 1 and 2, were mated 

 up in 1912. 



Pen 2, 1912. ^ 31(3 (weight 620 gr.) x % 283 (weight 620 gr.). 

 This pen gave 7 {/•(/ ranging between 680 and 880, and 8 pullets all 

 under 600. These birds were evidently breeding nearly true to small 

 size. In the following year the strain was further tested by mating 

 together two of these 1912 birds from Pen 2. They were ^ 232 (weight 

 690 gr.) and ? 678 (weight 470 gr.). They produced in 1913 10 j",/ 

 between 540 and 750 grams, and 3 $ $ all under GOO. 



The experiment shows that the original F^ j" ex Sebright x Ham- 

 burgh must have been producing some "bantam" gametes. Such 

 gametes, meeting with the gametes carried by pure bantams, gave rise 

 to birds which belonged to and bred true to the small bantam size. 



Pen 1, 1912. The other pen mated up with birds from the F^ x 

 Sebright cross consisted of a cock and 2 hens. The former was rather 



