Miscellaneous. 407 



The Sirenia, according to Brandt, are not Cetacea, but rather 

 purely aquatic Pachyderms, which, however, in accordance with our 

 principles of classification, may very well form a distinct order. — 

 Comptes Rendus, Sept. 7, 1863, p. 489. 



Note on the Lemming (Lemmus uorvegicus, Desm.). 

 By M. GuYON. 



The emigrations of the Lemmings, like those of the migratory 

 Locusts, are not periodical, and are attended, like them, by a greater 

 or less amount of damage in their course. The Norwegian Lemming 

 inhabits the highest parts of the mountains, where it lives chiefly 

 upon mosses and lichens. Like all its congeners, it sleeps through 

 the day, and only wakens at the approach of night. Its activity is 

 then extraordinary : it moves, as it were, in every direction at once — 

 tearing, gnawing, and murmuring. 



For some years the Norwegian Lemmings had not migrated ; but 

 they migrated again in the spring of the present year, although in 

 smaller numbers than usual. Towards Lillehamar, in the early part 

 of July many were still to be seen running about in the gardens, 

 and along the houses, and crossing the streets, which were completely 

 strewed with their dead bodies. Notwithstanding its tenderness, the 

 Lemming is strong and courageous. When pursued, it flies at first, 

 but soon turns and defends itself with teeth and claws : it bites 

 severely. Whilst on its defence, it utters very sharp cries. The 

 Lemmings often fight together ; and it seems probable that, under 

 certain circumstances, they devour each other. 



The cause of the emigration of the Lemmings has been supposed 

 by some naturalists to be the presentiment of a severe winter, by 

 others the deficiency of nourishment at the points where they live, 

 and by others, again, their too great multiplication in certain years. 

 Let us examine these three supposed causes of the emigration of the 

 Lemmings. 



1. A severe winter, of which the animals have a presentiment . — If 

 this were the case, the emigration would always take place at a period 

 more or less approaching winter. But the emigration took place this 

 year in the spring. 



2. The deficiency or scarcity of nourishment at the points inha- 

 bited by them. — The Lemming, as already stated, lives upon lichens 

 and mosses ; and these plants have not been less abundant on the 

 mountains this year than in preceding ones. 



3. The great multiplication of the animals in certain years. — This 

 cause appears the most plausible, and we may adopt it until a more 

 probable cause is discovered. 



It has been said that the Lemming, in its emigrations, follows in- 

 variably a direct line, and is stopped by no obstacle, however large ; 

 but no doubt a little of the marvellous has been intermixed with the 

 history of this interesting little mammal. In all probability, the 

 direction which it follows in its emigrations is given to it by the 

 declivity of the soil, so that it will always descend like water from 

 its mountains. 



