1911] Sivarth: Alas1i-a Expedition of 1909. 123 



beaver" at Boca de Quadra about five miles up a stream empty- 

 ing into the head of Marten Arm ; and at Bortage Cove, Revilla- 

 gigedo Island, he reported some cuttings of the previous year, 

 found at the head of the creek. At Thomas Bay he found a 

 chain of beaver ponds in the woods, but the beaver were gone; 

 all but one solitary individual which had apparently been living 

 there alone for several years. He left one front foot in a trap, 

 but escaped with his life. On the Taku River, some fresh cut- 

 tings were seen. 



As no specimens were secured the identity of this form with 

 the Vancouver Island race leucodontus is of course merely con- 

 jectural. 



Peromyscus maniculatus macrorhinus (Rhoads). 

 Rhoads "White-footed Mouse. 



Found at all the more southern mainland points visited, 

 and on several of the more southern islands. The mice collected 

 became less and less typical of macrorhinus as we advanced 

 northward, and the species evidently intergrades with hylaeus at 

 various points. In a general way Clarence Straits may be said to 

 be the dividing line between the two forms in extreme southern 

 Alaska, and typical macrorhinus was not found north of Wran- 

 gell Island. 



Specimens were secured at the following points : Boca de 

 Quadra, one (no. 8559), Annette Island, one (no. 8552), Gravina 

 Island, six (nos. 8553-8558), Chickamin River, six (uos. 8572- 

 8576, 9138), Revillagigedo Island, five (nos. 8568-8571, 9137), 

 Etolin Island, seven (nos. 8561-8567), Wrangell Island, two (nos. 

 8539-8540), and Bradfield Canal, ten (nos. 8541-8551). The 

 Museum collection also contains nine additional specimens from 

 Etolin Island, and from Helm Bay, Cleveland Peninsula (nos. 

 449, 450, 456, 461-464, 469, 470). 



Those from the more southern mainland points are apparently 

 most like typical macrorhinus. Northward the size diminishes and 

 intergradation with hylaeus appears to take place. The single 

 specimen from Boca de Quadra is rather small; those from the 

 Chickamin River, though clearly referable to this form, as is 

 evident from the large size of the skulls, are, in their external 



