1911] 



Sirarth: Alaslm Expedition of 1909. 



155 



are from these adjacent islands. They have one species of 

 mammal (Microfus coronarius) common to the two, and as far 

 as known occurring nowhere else ; and one other species 

 (Peroniyscus sitkeitsis) found on both which is not found, on 

 either of the large islands closest to them. The sooty grouse 



DISTRIBUTION 

 / 

 Denc/raqapus a fu//a/nosu3 



SOUTHEASTERN ALASKA 



Fig. 2. — Map showing the range of the sooty grouse {Dendragapus 

 obscurus fvliginosus) in southeastern Alaska. It occurs on some of the 

 more remote western islands of the archipelago, but is absent from others 

 lying nearer the mainland. 



(Dendragapus) is found on Coronation Island, but is absent from 

 Warren where apparently the spruce grouse (Canachites) occurs. 

 What the obstacle may be that stops a strong flying bird, and 

 yet permits the passage of small and feeble terrestrial mammals 

 it is hard to imagine. It is of interest to note in this connection 



