1922] Swarth: Birds and Mammals of the Siikine Region 173 



Another species, Synaptomys andersoni, has been described by 

 Allen (1903, p. 554), based upon a single specimen from Level Moun- 

 tain, near the headwaters of the Stikine Eiver. In all likelihood, 

 therefore, mice of this genus occur throughout the entire length of the 

 Stikine Valley. At present, however, with the few specimens extant 

 in collections, it is not possible to form an opinion as to whether or 

 not there are two species or subspecies in existence, at the head of 

 the river, and toward its mouth, respectively. 



Evotomys dawsoni dawsoni Merriam. Dawson Red-backed Mouse 

 An adult female (no. 30720) was taken at the Junction, June 4, 

 trapped during the day on a dry, poplar-covered hillside. It is. ap- 

 parently a typical example of Evotomys dawsani dawsoni. The next 

 obtained (no. 30721) was caught at Doch-da-on Creek, July 17, in a 

 tangle of alders, grass, and nettles bordering a slough. This specimen 

 is a niale, not fully mature but evidently referable to dawsoni. Some- 

 where in the section of the river between Doch-da-on Creek and Flood 

 G-lacier lies the dividing line between dawsoni and wrangeli. It would 

 be of interest to find if the two occurred together at any point. 



Evotomys wrangeli Bailey. Wrangeli Red-backed Mouse 

 Thirty specimens taken (nos. 30722-30751), three at Flood Glacier, 

 twenty-three at Great Glacier, and four at Sergief Island. Of this 

 series there is one old male (no. 30735, Great Glacier), with con- 

 spicuous gray patches over the hip glands, and showing rooted molars 

 with deeply worn surfaces. There are eleven more that may be termed 

 adult, as being in the adult pelage (though none of these has the gray 

 flank patches more than faintly indicated). The remainder are young 

 at various stages of growth. 



The red-backed mice from these three stations are all E. wrangeli, 

 indistinguishable from specimens at hand from "Wrangeli Island. The 

 range of that species is thus carried far inland up the Stikine Valley, 

 very close to the habitat of dawsoni, if in fact the two do not meet. 

 The four specimens from the uppermost station, Flood Glacier, show 

 no appreciable departure from the mode of wrangeli; there is no 

 indication here of intergradation toward the nearly adjacent dawsoni. 

 The two species, however, resemble each other so closely in form, 

 and in some pelages in color also, that wrangeli would seem to be a 

 coastal offshoot of dawsoni, bearing somewhat the same relation to that 



