564 Allen, Pattern Development in Teal. [ocV 



Dr. John C. Phillips tells me that the Congo Teal shows very 

 beautifully in a series of specimens from the same general region, 

 a variation in the degree of restriction of the individual pigment 

 centers. The common Mallard as I have shown in the article 

 above cited (Am. Nat., 1914, vol. 48, p. 483) frequently shows 

 under domestication, the development of white superciliary lines 

 that correspond in position with white areas which have in other- 

 species become a permanent part of the pattern. The normal 

 male Mallard has in the fully developed plumage, a white collar 

 at a point bounding the upper limit of the wine-colored neck. This 

 is merely the development of a white area at the point of contact 

 between the ear patches covering the sides of head and upper 

 throat, and the neck patches pigmenting the lower throat. (Here 

 the two sets of patches are of different colors.) In the domesti- 

 cated Black Mallard this white ring is often absent, on account of 

 the complete development of the two sets of pigment patches. I 

 have also seen a female Mallard in which a white half-ring was 

 present as an albinistic spot in just the place where it is com- 

 pletely developed in the male, showing that this is one of the con- 

 tact points between two pigment centers, a place of least color 

 formation, where, if restriction of pigment areas takes place, a 

 white mark will first result. Indeed the Anatidae seem especially 

 favorable for a more intensive study of this method of pattern 

 formation, and well merit special investigation as to the develop- 

 ment and transmission of partial pigmentation. Already careful 

 studies of rats, mice, guinea-pigs and rabbits have been made by 

 geneticists on these lines, and it is to be hoped that comparative 

 studies on birds will follow. 



Boston Society of Natural History, Boston, Mass. 



