No. 572] PATTERN DEVELOPMENT 483 



some of the details of these are shown in Figs. 54-56. 

 In the male wild mallard there is no white in the pattern 

 of the head and neck except a white ring at the base of 

 the neck. In one of the domesticated breed, shown in 

 Fig. 54, the crown patch was very beautifully marked 

 off, as in the pigeon (Fig. 49), by a white band from eye 

 to eye passing about the occiput. This duck was further 

 interesting in showing the median division of the two 

 neck patches, as a narrow white line running down the 



back of the neck medially, from the occipital stripe. An- 

 other duck shown in Fig. 55 had lost the neck patches 

 entirely, but showed the same occipital stripe bounding 

 the crown patch posteriorly, and the ear patches dorsally. 

 The ear patches still adjoin the crown patch anteriorly. 

 In Fig. 56 is represented another of these ducks in which 

 both ear patches are distinct and separate on either side 

 of the head. The crown patch appears as two narrow 

 lines of pigmented feathers which are not quite in con- 

 tact posteriorly. I have not obtained a satisfactory 

 explanation for the apparent tendency of this patch to 



