1926] Swarth: Birds and Mammals from the Atlm 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 dixoni. 



The type specimen of helloggae (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 

 dixoni. 



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 ruf escent 

 markings greatly reduced or altogether wanting. There are specimens 

 at hand from Baranof and Chichagof islands, and from Port Snet- 

 tishapi 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 Bp,y or from any other point on the long stretch 

 of coast line between Lynn Canal and Prince William Sound, and 

 dixowi 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. 

 Prom the Atlin birds it is widely different. The Atlin specimens are 

 predominantly gray, the Port Snettisham specimen dark and ruf escent. 

 Two young birds from Bennett (coll. of Allan Brooks), though inter- 

 mediate toward dixoni, are still much nearer to rupestris of the Atlin 



