Indigenous Icelandic Terrestrial Mammalian Fauna. 451 



although the Mus sylvaticu^ sometimes may be found white, 

 when such a thing occurs it is only a case of albinism, and 

 rare ; but the lemming in America is said regularly to become 

 white in winter, altliough not so completely so as the weasels. 

 Both in Spitzbergen and Nova Zembla a little white animal 

 has been observed. MM. Pachtisson and Ziwolka, daring 

 their winter stay in Nova Zembla, saw a little white animal 

 in their hut, which they, in their journal, call a mouse. Ac- 

 cording to Mr. Ziwolka it was larger than a common domestic 

 mouse, and therefore could not have been a white individual 

 of that species ; it was doubtless a lemming. According to 

 Von Baer there are two species of lemming found in Nova 

 Zembla, one of which he considered identical with the Myodes 

 hudsonius. 



" As the lemming is an Arctic animal, it must pass a 

 longer night of winter than ordinary torpidity could survive. 

 Some arrangement for a winter supply is therefore plainly 

 necessary, and it is scarcely possible to conceive anything 

 better adapted to the pm-j30se than that described by Hen- 

 derson. 



" I have, therefore, no doubt in my own mind that the 

 economic mouse of Iceland is a lemming ; and as Greenland 

 is the nearest point where lemmings have been found, I think 

 it a fair conjectm'C, until rebutted by direct evidence, that 

 the species found there is the American lemming, Myodes 

 Jiudsoniusy 



In accordance with this notion, Murray's map Ixxv. (of 

 the geographical distribution of the lemmings) represents 

 Iceland as a lemming-country ; and his map ci. (of the pro- 

 vinces of the terrestrial Mammalia) represents Iceland as a 

 country with a Western or Nortli-American fauna. 



I cannot accept either these arguments or their results. 

 Let us even admit provisionally that the account given us of 

 these mice, that they collect great stores of food, and that 

 they dig hollows for the preservation of this, for their dwelling- 

 place, and also for their impurities, may apply in general to 

 certain species of lemmings ; there are nevertheless inter- 

 woven several particular circumstances which in my eyes 

 prove that it does not relate to Rodents of this group, but 

 must refer to such as belong to the same group as the common 

 mouse. In the first place, both statements represent the 

 principal food of this mouse as consisting of berries, especi- 

 ally ^-lr/>«/^/.s-berries ; and the carrying of these home is in- 

 deed the object of its journeys. But the Arvicolines and 

 lemmings are addicted chietly to quite a diflcrent kind of 

 vegetable food, as indeed is proved both by observation and by 



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