450 Scientific Intelligence. — Zoology. 



in Sweden. When not migrating, lemmings inhabit burrows, 

 either simple or ramified at one or more of their openings, dug 

 in the little mounds of earth so common in Lapland, and which 

 are generally produced by the stump of a pine having become 

 reduced to vegetable earth. Constantin Gloger enumerates 

 only five species of the Linnean genus Mus, which construct 

 nests. These are Mas messorius, M. musculus, M. agrarius, 

 M. sylvaticus, and M. mmutus. To this list it is necessary to 

 add M. lemnus. Its nest is cylindrical, about 18 centimetres 

 long, by 6 broad, more capacious below than above, with an 

 opening at its anterior extremity. One of those we brought 

 with us was composed of the leaves of a grass which could not 

 be recognised, mingled with fragments of Betula nana, Empe- 

 trum nigrum, Vaccinium Vitis-idea, Cenomyce rangiferina, G. 

 pyxidata, Cladonia de/ormis, and Stereocaulon tomentosum. Lem- 

 mings are very courageous ; they try to defend themselves 

 against every opponent by whistling and barking ; and they 

 fight with fury among themselves. When two of them are put 

 into a cage together, it is necessary that one should yield to 

 the other. Bears, foxes, wolves, martins, ermines, dogs, birds 

 of prey, and even rein-deer, destroy them in great numbers. 

 Their animal temperature is rather high ; a medium of four 

 observations afforded me + 39° 5" Cent. 



In relation to the statement made by M. Martins, that rein- 

 deer sometimes feed on lemmings, M. Roulin mentioned that 

 an analogous fact is observed among many other species of 

 herbivorous mammifera, which appear capable of readily ac- 

 commodating themselves to an animal nutriment when a vege- 

 table one fails them. Thus, during the passage of a cloud of 

 migratory locusts, we see fowls, sheep, and cows searching for 

 them eagerly, on purpose to feed on them. Perhaps some of 

 the epizootical diseases which ravage our flocks may be as- 

 cribed to this caust . It is known, moreover, that in New 

 Holland, sheep, at a certain period, eat their young. M. Rou- 

 lin likewise remarked, that the lemming is not the only species 

 of mammifera which sometimes appears in innumerable mul- 

 titudes, and he mentioned, among the animals of France, the 

 campagnols of Beauce, the rats of Bretagne, &c. Many other 

 animals, and locusts in particular, in like manner follow a 

 straight line in their migrations. Finally, the great battles in 



