1926] §warth: Birds and Mammals from the Atlin Region 99

My own conviction of the desirability of including both series under
the same name, rests upon the facts that birds from neither place are
representative of the extreme manifestation of the Alaskan race; and
that the differences between them are due to one series (from Eagle)
illustrating intergradation toward rupestris, the other (from Prince
William Sound) illustrating to some slight degree intergradation
toward dixon.

The type specimen of kelloggae (Mus. Vert. Zool., no. 1169, adult
male, Montague Island, Prince William Sound, July 7, 1908) can be
matched almost exactly by a selected specimen from Demarcation
Point, Arctic coast of Alaska (Mus. Comp. Zool., no. 68933, adult male,
July 10, 1914). Of the several Prince William Sound specimens, as
with one adult male from the nearby mainland point of Seward, it
seems to me that in whatsoever features they differ slightly from the
mode of birds from northern Alaska, they show some approach toward
dizoni.

For all these reasons I am regarding the name kelloggae as having
been applied to a variant of the Alaskan mainland subspecies, and,
with regard to the true features of this same subspecies, properly
applicable to the whole aggregation.

There are fewer specimens of dixoni available than of either of the
other subspecies here under consideration, but nevertheless this rela-
tively scanty material suffices to show that it is a well marked form,
and to indicate the range of the subspecies with fair accuracy.

Dixoni is a dark, slaty-colored race, with, in the male, the rufescent
markings greatly reduced or altogether wanting. There are specimens
at hand from Baranof and Chichagof islands, and from Port Snet-
tisham and White Pass on the adjacent mainland. There is as yet no
proof of the extension of the range of this form south of Christian
Sound or north of White Pass. However, I have seen no rock ptar-
migan from Yakutat Bay or from any other point on the long stretch
of coast line between Lynn Canal and Prince William Sound, and
dixom may be found to extend for some distance in that direction.

The one specimen from Port Snettisham is a young female (Mus.
Vert. Zool., no. 9796, August 29,1909). Exactly comparable plumages
are at hand from Atlin, from near Bennett, and from northern Alaska.
From the Atlin birds it is widely different. The Atlin specimens are
predominantly gray, the Port Snettisham specimen dark and rufescent.
Two young birds from Bennett (coll. of Allan Brooks), though inter-
mediate toward dixoni, are still much nearer to rwpesiris of the Atlin