1909] The 1907 Alexander Alaska Expedition. 259 
At Hooniah, Chichagof Island, Hasselborg found some old 
dilapidated dams which were evidently quite ancient. Dixon 
states in his notes that the beaver is undoubtedly exterminated 
on Chichagof. The beaver on Chichagof was doubtless the same 
form as on Admiralty, although it is not improbable that this 
form should show slight differences considering the signifi- 
cance of Chatham Strait as a faunal barrier between these two 
islands. 
Peromyscus sitkensis Merriam. Sitka White-footed Mouse. 
A series of seventeen specimens are in the collection which 
were secured at Red Bluff and Rodman bays, and Peril Strait, 
Baranot Island. These agree minutely with the topotype series 
in the Biological Survey collection. Stephens reports this 
species rare at Red Bluff Bay and Peril Strait, but fairly com- 
mon at Rodman Bay. 
The Chichagof material consists of fourteen specimens, 
chiefly from Hooniah. Single specimens were taken at Fresh- 
water Bay, Idaho Inlet and Port Frederick. This series aver- 
ages somewhat smaller in all its measurements than the Ba- 
ranof material, in which respect it approaches macrorhinus. 
This apparent intergradation is difficult to account for, as typ- 
ical sitkensis holds an intermediate geographical position. 
At Hooniah this species was found fairly abundant by 
Dixon in the abandoned houses, to which retreats it seemed to 
be confined. 
Peromyscus hylaeus Osgood. Admiralty White-footed Mouse. 
This species was found only on Admiralty Island where it 
occurred in great abundance in the littoral zone to which it is 
chiefly confined. A series of one hundred and seven specimens 
are in the collection. These agree with the topotype series 
from Prince of Wales Island. 
At Windfall Harbor ninety-two specimens were secured. 
Stephens and Dixon found them here in great abundance, con- 
fined, however, to the alder thickets near the beach. Dixon 
found them common at Hawk Inlet in abandoned houses. At 
Mole Harbor Stephens found them fairly numerous. 
