MENDEL'S SECOND LAW 



69 



If the single comb be supposed to be the wild type, 

 then Pea and Eose represent dominant mutant types 





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Fig. 31. — Combs of fowls, single, a; pea, b; rose, c; and walnut, d. 



Neither produces any single comb, if the races are homo- 

 zygous for Pea or for Eose respectively, but when crossed, 

 the Pea comb brings in the normal recessive allelomorph 



