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 tliose 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 ^/ /cast 22.5 per cent (and at most 45 per cent) crested 

 offspring. The 37 offspring are all 7ion-crestcd. 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. 



