INHERITANCE OF CREST. 



1. Recessiveness of Plain Head. 



The following table contains, extracted from the general table, 

 those experiments that give an answer to the question whether non- 

 crested heads are recessive to plain heads. All parents are non-crested. 



Table 1. — Progeny of Non-Crested Parents. 



[The superior and inferior letters C (crested) and c (non-crested) indicate the condition of the 

 grandparents, o signifies original stock, of whose ancestry, consequently, nothing is known directly. 

 The numbers in columns "Father" and "Mother" are those of the leg-bands.] 



Thus of 102 offspring of two non-crested parents all were non- 

 crested. In table 1 are included several cases — Experiments 605, 609, 

 619, 623, and 725 — where from one-fourth to three-fourths of the grand- 

 parentage is crested. In these experiments Galton's law calls for an 

 average of at least 22.5 per cent (and at most 45 per cent) crested 

 offspring. The 37 offspring are all non-crested. Galton's law simply 

 does not apply to cases of alternative inheritance. 



2. The Detection of Homozygous Crests and the Gametic Compo- 

 sition OF Heterozygotes. 



If crest is an alternative characteristic we should expect to find 



some (one in three) homozygous dominants which always throw only 



crested birds, whether mated with a crested or a non-crested bird. The 



following experiments were arranged to test the purity of crested birds. 



