70 INHERITANCE OF CHARACTERISTICS IN DOMESTIC FOWL. 



From table 56 it appears, summing all cases, that there are more left- 

 lopping offspring than right-lopping as 161 to 124 or as 56.5 per cent to 

 43.5 per cent and that this excess holds whether both parents are right- 

 lopping, or both left-lopping, or the mother left and the father right. Only 

 in the case when the mother is right-lopping is there a majority of offspring 

 of the same sort, but here the numbers are too inconsiderable to carry 

 much weight. Although there is not clear evidence of any sort of inherit- 

 ance, it is probable that the position of the lop is not determined by a 

 single factor, but by a complex of factors. 



The conclusion that right and left conditions are not simple, alter- 

 native qualities accords with the results obtained by others. Thus Larrabee 

 (1906) finds that the dimorphism of the optic chiasma of fishes (in some 

 cases the right optic nerve being dorsal and in others the left) is not at 

 all inherited, but in each generation the result is strictly due to chance. 

 This is, perhaps, the same as my conclusion that the hereditary factors are 

 complex. Lutz (1908) finds that in the mode of clasping the hands inter- 

 digitally the right thumb is uppermost in 73 per cent of the offspring when 

 both parents clasp with right thumb uppermost, but in only 42 per cent 

 of the offspring when both parents clasp with left thumb uppermost. The 

 mode of clasping is inherited, but not in simple Mendelian fashion. 



