62 



NOKTH AMERICAN FAUNA. 



[No. 37. 



postpalataJ length, 36.7-38 (37.5); length of nasals, 38.9-41.5 (40.6); 

 zygomatic breadth, 62-67.7 (64.8); breadth across mastoids, 43.2-44.6 

 (43.8); least interorbital breadth, 22.6-26 (24.3); breadth of rostrum, 

 21,1-23.5 (22.2); maxillary tooth row, 21.8-22.5 (22.2). Adult 

 female: ^ Condylo-basal length, 93.7; palatal length, 51.6; postpalatal 

 length, 37.7 ; length of nasals, 39.6; zygomatic breadth, 61.8; breadth 

 across mastoids, 42.3; least interorbital breadth, 24.5; breadth of 

 rostrum, 21.3; maxillary tooth row, 22. 



Remarks. — -This form is apparently an incipient species or race in 

 which the characters have not as yet become fixed. It shows the 

 same tendency to become brown that appears so strikingly in M. van- 

 couverensis, and to a lesser degree in M. olympus. Its range is appar- 

 ently limited to the region about Glacier Bay (since specimens from 

 Yakut at Bay, White Pass, and Juneau are referable to caligata) but 

 whether it is actually isolated is not known. 



Specimens examined. — 'Ten, from type locality 



MARMOTA CALIGATA SHELDONI Howell. 

 Montague Island Marmot. 

 Marmota caligata sheldoni Howell, Proc. Biol. Soc. Washington, XXVII, 1914, p. 18. 



Type locality. — ^Montague Island, Alaska. 



Distribution. — Known only from type locality. 



Characters. — Similar to caligata, but size smaller and nasals shorter. 



Color. — ^Upperparts mixed white and black, whitest on fore back, 

 shading to cinnamon-buff on rump; underfur fuscous, shading on 

 hinder back to natal brown; top of head black; a large white patch 

 on face in front of eyes; sides of face mixed blackish brown and cinna- 

 mon; tail deep cinnamon-buff or ochraceous-buff, mixed with black, 

 the bases of hairs chestnut-brown; underparts white, tinged with 

 cinnamon. 



Skull. — Similar to that of caligata, but decidedly smaller; nasals 

 shorter and broader posteriorly, terminating usually about on a line 

 with ends of premaxillae ; premaxiUae narrower. 



Measurements. — ^Adult male topotype: Total length, 670; tail ver- 

 tebrae, 185; hind foot, 94. Adult female topotype: 640; 180; 90. 

 Skull: Adult male: 3 Condylo-basal length, 89.5-96.6 (average, 93.6) ; 

 palatal length, 51.2-55.4 (53.3); postpalatal length, 34.3-37 (35.5); 

 length of nasals, 35-39 (37.3); zygomatic breadth, 61.5-63.4 (62.4); 

 breadth across mastoids, 41.3-42.4 (41.9); least interorbital breadth, 

 22.5-23.8 (23.3); breadth of rostrum, 20.5-21.8 (21.2); maxillary 

 tooth row, 22.2-23.1 (22.5). Adult female :i Condylo-basal length, 

 88.7; palatal length, 50.2; postpalatal length, 34; length of nasals, 37; 

 zygomatic breadth, 59.4; breadth across mastoids, 39.7; least 



1 One specimen from type locality. » Fom- specimens from type locality. 



2 Seven in collection Mus. Vert. Zool., Univ. of California. 



