162 



THE AMERICAN NATURALIST [Vol. XL VII 



fications of the Jungle, usually by the loss or non-devel- 

 opment of a part. I know of no other distinctive pattern 

 in chickens, such as, for example, that exhibited by the 

 Mallard in ducks. 



• Brown Leghorns, Other Th 



Lops. Blade 

 Usually abs 



The feather patterns fall into two groups, viz., those 

 associated with sexual dimorphism and those not so asso- 

 ciated. In the male there is no pattern of the first group. 

 But penciling of the type found in the Dark Brahma 

 female appears never to occur in the male and therefore 

 belongs in the second class. Stippling is also usually 

 distinctive of the adult female, but it occurs in the young 

 male and under certain conditions (heterozygosis) in the 

 adult male. In the Jungle female the stippling often 

 approaches very closely the form of narrow concentric 

 lines or vermiculati'ons. Possibly the stippling of the 

 Brown Leghorn female is due to the breaking up of such 



