116 ON THE PLUMAGE OF THE RED GROUSE. (Jan. 17, 
colour. Back very black, the feathers edged and barred with dark 
brown, greater wing-coverts black, with here and there slight brown 
markings; upper tail-coverts very dark brown with lighter brown 
marks, shading to nearly pure black at the tail. Chin black, throat 
very deep reddish brown ; breast black, some of the feathers slightly 
edged with brown, which turns to white at the centre of the breast, 
the sides showing more decided brown markings ; under tail-coverts 
same as sides, but the markings more distinct still. 
This bird approaches to a melanism; but as I have often come 
across specimens closely resembling it, I have described it as a type 
of one of the variations. 
No. 8. Female, Dec. 3, 1879.—Back of head and neck light 
brown, marked with black bars and spots. Back, greater and lesser 
wing-coverts, and tail-coverts light brown marked with black bars, 
some of the feathers having black spots; the tips of many of the 
feathers again have a yery light brown spot, giving it a very mottled 
appearance. Outer edges of primaries slightly marked with white. 
The whole of the breast, sides, and under tail-coverts light brown, 
shading to darker brown in the centre, each feather having one or 
more black bars—the feathers in the centre and sides also being edged 
with white, as are also the under tail-coverts. 
This and No. 4 most nearly resemble each other, the latter being 
probably the older bird. 
Now I think it will be admitted that the specimens I exhibit 
should not be, as I maintained before, regarded as “‘ varieties”’ in 
the vague and ordinary sense of that word. It seems to me that we 
should regard them as instances of individual differences or polymor- 
phisms—just as in the case of the Ruff (IZachetes pugnax), which 
exhibits a degree of variability in its seasonal adornment more con- 
spicuous, I allow, than that of the Grouse now before us, but far 
less permanent, since the difference in the Grouse would appear to 
remain, if not throughout the year, for at least several months, 
while that in the Ruff is confined to but a few weeks in the spring 
or early summer. Thus, if my contention be just, we have in the 
Red Grouse—the only species of birds according to the opinion of 
most ornithologists which is peculiar to the British Islands, and a 
species which in the judgment of the best authorities is itself the 
modified descendant of a far more widely distributed species, the 
Willow-Grouse (Lycopus albus)—an amount of individual variability 
capable of still further and perhaps indefinite modification as to 
colour, should occasion arise whereby such modification might be 
rendered necessary for the persistence of the stock. 
