Nos. 618-619] SHORTER ARTICLES AND DISCUSSION 357 



F"i FemaJe Gametes 



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priately representing 1 F x male and 1 F 1 female gamete free, 

 like the constituents of a united sperm and egg, to interact in 

 the zygote and in subsequent ontogenesis. 



Some of these ratios, such as exist in Cases Nos. V, VI and 

 IX, are much more difficult chemically to contrive than others, 

 such as Nos. I, II, III, IV and X. It is not surprising, then, 

 that nature provides more readily cases in inheritance repre- 

 senting the latter ratios, while the former are being found only 

 by the most diligent genetical study. Not all of these ratios 

 have yet been found in nature by experimental breeding, but, 

 from time to time, a geneticist reports the discovery of a new 

 di-hybrid F 2 ratio which proves to be a member of this series. 

 Doubtless all of them will be found in time, but without intro- 

 ducing the special phenomena earlier referred to, Series A. con- 

 sisting of 10 cases, exhausts the possibilities of F 2 phenotypic di- 

 hybrid ratios. 



