Vol. XIV 
= : Aes Vichy ue - 
1897 CHADBOURNE ox Individual Dichromatism 35 
black, and at least two varieties of brownish coloring matter 
(so-called ‘ pigments’), were present, not only after the red-brown 
shade appeared in the plumage, but also in every feather of the 
gray type, except three of the ‘first’ and one from the mature 
gray plumage. 
The black pigmented matter was made up of oblong-oval or ellip- 
tical granules, never of small rods, as in the domestic pigeon ; 
but it is well-known that the shape varies in different kinds of 
birds. The amount of black granular matter was always rela- 
tively small, and it was chiefly confined to the deeper cell layers. 
Isolated spots of true black were frequent in the central cells, 
while around them there was often much dark brown. 
The drown pigmented material was found in the form of a pale, 
nongranular, diffused stain, extending through all kinds of feather 
tissue; and also as brown granules, of various tints and sizes, 
which were usually in narrow lines or groups, instead of being 
generally distributed, like the nongranular stain. The two 
extremes were connected by a complete series of intermediate 
forms, showing every gradation between the dark chocolate and 
- the ochraceous tint; while the size of the granules also varied 
considerably, and it was at times not easy to distinguish the homo- 
geneous from the very finely granular. The black and very dark 
brown granules perhaps also intergrade, but on this point I can_ 
not speak with certainty. 
As the red phase developed, more and more red-brown granules 
and diffuse stain seemed to be present in the feathers, at times 
obscuring, or completely hiding the dark markings beneath (Plate 
I, fig. 1), or grouped and scattered about the black in the deeper 
layers, caused various shades and tints of brown andtawny. Asa 
rule the seemingly black color proved to be the result of either a 
dense mass of dark brown granules, of the greater thickness of the 
darker portion of the specimen, or of both continued, plus an un- 
derlying area of true black in the deep tissues. The pure rufous and 
bright tawny portions had the coloring matter chiefly in the more 
superficial cell layers, and either little or no true black beneath; 
while the streaks and lines of brownish granules suggested the 
‘bast-fibre layer’ of certain plants, and the tawny effect was 
heightened by the diffuse nongranular stain (Plate I, fig. 4, 6 
