GROUSE 3093 
sented by a very nearly allied form—so much so indeed that it is 
only at certain seasons that the slight difference between them can 
be detected. This form is the L. rupestris of authors, and it would 
appear to be found also in Siberia (Ibis, 1879, p. 148).2  Spits- 
bergen is inhabited by a large form which has received recognition 
as L. hemileucurus, and the northern end of the chain of the Rocky 
Mountains is tenanted by a very distinct species, the smallest and 
perhaps the most beautiful of the genus, L. leucurus, which has all 
the feathers of the tail white. The very curious and still hardly under- 
ihe 
BLACKCOCK, 
stood question of the MouLr of the Ptarmigan could not be discussed 
here, and reference can only be made to the shedding of its CLAWS. 
The bird, however, to which the name of Grouse in all strict- 
ness belongs (see p. 388, footnote 2) is Tetrao tetrix—the Blackcock 
and Greyhen, as the sexes are with us respectively called. It is 
distributed over most of the heath-country of England, except in 
East Anglia, where attempts to introduce it have been only par- 
tially successful. It also occurs in North Wales, and very generally 
1 Examples from Greenland have borne the name of L. reinhardti, others 
from Newfoundland Z. welchi, and the islands of Unalaska and Atka are said to 
present local forms distinguishable as nelsoni and atkhensis respectively (cf. 
Ridgway, Man. N. Am. B. p. 201). 
2 T am indebted to Prof. Mitsukuri for specimens from Japan ; but I dare not 
yet characterize them. 
