Mar. 4. 191S Winter Egg Production of Rhode Island Reds 



573 



In Table XIII is shown the classification of the flocks of 191 6-17, 

 arranged by families. Each individual is classified twice. According to 

 one classification (method A) our endeavor has been to ascertain as 

 closely as our best judgment would permit, the true status of each in- 

 dividual. In method B, however, we have given the benefit of any di .ubt, 

 to the winter cycle and have listed every bird in the positive column 

 that could possibly be considered as having a winter cycle. 



Section A gives the ratio of 61 individuals with a winter cycle to 174 

 without. This is close to the i to 3 ratio — viz, expected 58%" to 176X — 

 for a simple Mendelian case of inheritance. According to method B, 

 however, the ratio approaches closely to equality. 



Table XIV gives the ratios for the flocks as a whole for 1913-14 and 

 191 5-1 6, in addition to 1 916-17, and the grand total. The years vary 

 somewhat, but the total, 147 to 388, is perhaps merely a deviation from 

 the expected 1 33^ to 401 X> the deviation being in the direction expected, 

 on the assumption that birds without the genes for a winter cycle may 

 exhibit a false cycle. 



Table XIV. — Number of individuals classified according to the presence or absence of the 

 winter cycle for the years igij-14, igi^-i6, and igid-iy 



For method B the observed ratio for the three seasons is 289 to 318. 



Mass figures of the sort just given are merely suggestive, since the 

 ratio I to 3 holds only under certain conditions. However, an examina- 

 tion of the proportions in which the two types occur among the progeny 

 of a single female, and in some instances of the progeny of one male by 

 several females, favors the suggestion given above. At the same time, 

 the gametic constitution of the parents can not be made out with a 

 satisfactory degree of accuracy. To be sure, one can assign a gametic 

 constitution to many individuals, but it is impossible to check these by 

 reference to preceding years, mainly because the number of progeny 

 from a single pair in the earlier years was too small to afford critical 

 evidence. Since prospective matings are likely to furnish critical 

 evidence on the point in question, it seems advisable to defer any attempt 

 at a solution of this phase of the problem for the present. 



