1911] Swarth: Alaska Expedition of 1909. 133 



Twenty-two specimens were secured (nos. 8714-8734, 9120), 

 seventeen from Coronation, and five from Warren Island, twenty- 

 one of these being preserved as skins, and one in alcohol. These 

 examples are quite uniform in every respect, and none exhibits 

 any marked divergence from the general type. One or two 

 have a greenish stain on the underparts, which is probably wholly 

 adventitious, possibly caused by some of the wet vegetation in 

 which they live. 



Fiber zibethicus spatulatus Osgood. Northwest Muskrat. 



A small series of muskrats taken at Portage Cove, Revillagi- 

 gedo Island, are in many respects very similar to specimens at 

 hand from Yukatat Bay, Alaska, and I provisionally refer them 

 to this Alaskan race. Ten specimens of spatulatus from the 

 Yukon Valley are more reddish in color, and apparently smallei', 

 though there are no measurements with the skins. Compared 

 with examples of osoyoosensis from northern Washington 

 these island muskrats are paler colored and smaller, with short 

 tails and proportionately large feet. The skulls are short, but 

 very heavy and massive, with wide spreading zygomatic arches. 

 The five specimens secured are quite uniform in size and color, 

 as well as in the appearance of the skulls. They measure as 

 follows : 



No. Sex Length Tail Hind Foot 



8355 d' 490 210 75 



8356 c? 510 220 75 

 8354 S 510 220 -78 



8357 S 480 195 72 

 8353 c? 495 210 75 



SKULL MBASUEEMENTS. 



Alveolar 

 Zygo- Interorbital Length of 



Basal matic Mastoid Constric- Upper 



No Sex Length Width Width tion Nasals Diastema Molars 



8353 c? 57 40 24 6.8 22 22 15 



8356 t? 58 40.5 35.5 6.5 22 22.5 14.5 

 8355 c? 57.5 40 25 7 22.5 22.5 14 



8357 5 55.5 38.5 23.5 7 21 21 14 



8354 S 57 39.5 25 6.2 22.5 22 14.8 



Eevillagigedo Island was the only place during the entire 

 summer where muskrats were encountered. The meadows border- 



