Merriam — Four JVeic Arctic Foxes. 169 



insular species; the small one a straggler from Hall or St. 

 Matthew [or some other] Island, the others hybrids between 

 these two, or in some cases perhaps, stragglers from the main- 

 land. On this assumption I have named the large form jjribi- 

 lofensis. In winter the pack ice from the north often reaches 

 St. Matthew Island and sometimes pushes south to the Pribilof s. 

 Tlie distance between St. Matthew and St. Paul is about 225 

 statute miles; that between Nunivak (from which we have no 

 specimens) and St. Paul is even less. But wherever the animals 

 come from, the fact is well-known that when the pack ice 

 reaches the Pribilofs, white foxes come ashore on the Islands. 

 They have been seen to do this repeatedly. When observed, 

 they are pursued and killed, if possible, in order to prevent in- 

 terbreeding with the native blue foxes. 



On Bering Island, on the Siberian side of Bering Sea, there 

 appear also to be two forms: the mainland species {lagopus) and 

 a lai'ge insular species hei-e named beringensis. 



l^elayes. — The characteristic markings of the Arctic foxes 

 are: In tinnter pelage, white throughout, the only marking be- 

 ing the small black pad on end of nose; in summer jielage, head, 

 back, a cross-bar over shoulders, outer side of fore and hind 

 legs, upper surfaces of fore and hind feet, and stripe on upper- 

 side of tail, brownish dusky, usually darkest on top of head and 

 rump; face strongly, feet moderately mixed with white hairs; 

 ears strongly edged with white; chin grayish dusky; underparts 

 soiled whitish or buffy, becoming strongly buffy on flanks. 



The Blue fox of the Pril)ilofs is a sooty-blue all over at all 

 seasons. 



Sexual differences. — As usual among foxes the males are 

 somewhat larger than the females. Among the Arctic foxes the 

 difference in size of skull is usually not great, but the large 

 upper molar, and the carnassial above and below are noticeably 

 larger in the males. 



The Arctic foxes here recognized in North America (including 

 Bering Island but excluding Greenland) are as follows: 



Vulpes lagojius (Linn.). Type locality Lapland. Believed 

 to occur on Bering Island. 



l^uljjes lagopus innuitus nob. Type locality Point Barrow, 

 Alaska. Ranges from Alaska to Baffin Bay. 



