100 University of California Publications in Zoology [Vol.30 



region. The Port Snettisham bird differs but slig-htly from skins from 

 Seward Peninsula and rather more so from young birds from the 

 Arctic coast of Alaska. It is somewhat darker colored. It can be 

 matched very closely by a young bird from Kodiak Island. 



A pair of adults from Mount Dewey, on the Alaska side of the 

 White Pass, are of especial interest. These are from the D. R. Dickey 

 collection : no. 13462, female, July 26, 1923 ; 13463, male, August 7, 

 1923. The male bird is exactly like others from Baranof and Chiehagof 

 islands. The female is distinguished from other rock ptarmigan by 

 dark tone and extremely rufescent coloration. It differs far more 

 from Atlin females, and indeed from a female from Bennett, on the 

 opposite side of White Pass, than from those from northern Alaska. 

 Whether or not this specimen represents the mode of female dixoni, 

 in its typical form, on Baranof and Chiehagof islands remains to be 

 seen. So far as I know there are no such specimens extant in any 

 collection at this time. 



The present study takes into account certain phases of geographical 

 variation in the North American rock ptarmigan, and suffices to make 

 clear some certain points, but there still remains far more work to be 

 done before any satisfactory understanding can be reached of the 

 manner of variation over the whole of the range of this species, or 

 several species, as the ease may be. 



It may be pointed out that I have not touched upon the relations 

 of the New World Lagopus rupestris and the Old World Lagopus 

 mutus, which are admittedly close; the two forms may well be con- 

 specific, as has been claimed (see Hartert, 1921, p. 1871). It is con- 

 ceivable that the ptarmigan o^ northeastern Siberia is the same as the 

 Alaskan subspecies here designated Lagopus rupestris kelloggae. The 

 latter certainly attains its extreme of differentiation from rupestris 

 on the Alaskan coast most nearly approaching Siberia. 



I have not attempted to take into consideration such variation a.s 

 occurs among the several forms described from the Aleutian Islands. 

 There, too, a comprehensive study should help toward an understand- 

 ing of the relationships of Old World and New World forms. The 

 few specimens that I have examined from the Alaska peninsula exhibit, 

 it seems to me, intergradation from kelloggae toward nelsani, of the 

 easternmost Aleutian Islands, but there is not at hand material to 

 demonstrate this satisfactorily. 



