1911] Swarth: Alaska Expedition of 1909. 129 



At this time, September, the mice were still breeding, and 

 many of the females secured contained embryos, six or seven in 

 number. Fifty specimens were obtained (nos. 8669-8713, 9121- 

 9125) a large proportion of them being' young of various ages. 

 All are in summer pelage, short haired and rather shabby and 

 worn in appearance. 



Although I have considered these specimens as M. drummondi 

 they are not typical of this species. In size they are uniformly 

 very large, a peculiarity of northern examples of the species 

 which has already been commented upon by various writers. The 

 skull is large and heavy, with the exception of the audital bullae. 

 These are actually smaller than in typical drummondi, propor- 

 tionally much more so. The zygomata are wide spreading. It 

 is decidedly suggestive that in all respects as they depart from 

 typical drummofidi they approach Microtus admiraltiae (Heller 

 1909, p. 256), and they might be considered as intermediate be- 

 tween the two forms, but for their strongly curved inbisors, in 

 which particular they have not varied. There can be little doubt 

 however, that it is with this species that the affinities of 

 Microtus admiraltiae lie, as seems evident from the relative 

 geographic position of the two forms, as well as their close gen- 

 eral resemblance. 



Sixteen specimens of Microtus drummondi, eight males and 

 eight females, taken on the Taku River, measure as follows: 

 length, 157.4 ; tail vertebrae, 46.4 ; hind foot, 20.2. Skull : basal 

 length, 23.2; zygomatic width, 14.7; mastoid width, 11.3; dias- 

 tema, 7.9 ; length of nasals, 7.1. 



Microtus macrurus Merriam. Olympic Meadow-mouse. 



Possibly quite generally distributed over the southern part 

 of the archipelago, though there were a number of islands where 

 we failed to secure any, or to see any indication of their presence. 



Sixty-two specimens were obtained (nos. 8609-8668, 9126, 

 9127) at the following points: Kupreanof Island, Kuiu Island 

 (Three-mile Arm; Port McArthur), Prince of Wales Island 

 (Port Protection; Calder Bay; Shakan; Klawak Salt Lake); 

 Dall Island; Mitkof Island; and on the mainland at Bradfield 

 Canal and Thomas Bay. At most points they were decidedly 



