THE SPLIT OR Y COMB. 



9 



is opposed to any hypothesis is the appearance of some Y-combed offspring; 

 and to account for this the hypothesis is suggested that the germ-cells of 

 some parents with oo comb contain traces of the l-comb determiner. The 

 word "traces" is used because the median element in these Y-combed off- 

 spring is practically always very smaU. It is fair, consequently, to con- 

 clude that OCX 00 gives oo-combed, and occasionally combless, offspring. 

 This conclusion is further supported by the statistics derived from extracted 

 00 comb of all generations bred inter se, which give: Y 11, oo 427, and 

 no comb 8, where the 11 Y-combed birds are those just referred to as 

 progeny of Fj parents. The non-median comb, consequently, probably 

 contains onlj'- non-median germ-cells. 



Table 6. 



The mating of extracted I comb and Y comb, both of the second (or 

 later) hybrid generation, gives the following distribution of types in the 

 offspring (table 6) : Y comb 95 (49 per cent) ; I comb 95 (49 per cent) ; 

 00 comb 4 (2 per cent). In detail the results given in table 6 accord badly 

 with the second hj^othesis, which demands some famiUes with 100 per 

 cent Y comb. 



The mating of extracted oo combXY comb, where both parents are 

 of the second hybrid generation, gave the distribution of comb types in 

 the 6 families that are recorded in table 7. 



Table 7. 



