330 



THE MUSEUM. 



restlessly as though it were August. 

 The ground was frozen, and the sun- 

 light had merely warmed and dried the 

 tangled mat of dead grass upon the 

 surface. At various points I found the 

 openings of tunnels, which I took to 

 be the path-ways of the crepuscular 

 schrews, shy little creatures, that 

 towards sunset come to the surface 

 and forage during the twilight. 



Omitting reference to the winter 

 habits of the familiar squirrels and 

 woodchuck, or marmot, let us consid- 

 er briefly the two small rodents found 

 here that are also hibernating animals, 

 the jumping-mouse {Zapus lutdsoiiiiis) 

 and the white-footea mouse [Hcspcr- 

 oinys Iciicopiis). These two mice, 

 popularly so called, hibernate with 

 great regularity in one sense but differ 

 inter sc in another. The former, once 

 torpid remains so until spring, a few 

 warm days in winter failing to rouse 

 them; but the white-footed mouse 

 seems simply to sleep soundly rather 

 than grow torpid, and responds with 

 considerable promptness to any dis- 

 turbance. The jumping-mouse builds 

 a nest of leaves and grass at a con- 

 siderable depth from the surface of the 

 ground (not a "ball of mud," as stated 

 in the "Encyclopedia britannica," art. 

 "Jerboa"), and once fairly settled 

 therein, is beyond the various sudden 

 , changes of our winters; the white- 

 footed mouse, on the contrary, utilizes 

 an old bird's nest or has a resting- 

 place beneath a log or in a half-de- 

 cayed stump. In such positions, of 

 course, the occupant is more likely to 

 be disturbed and is also directly ex- 

 posed to the varying temperature. Is 

 it to meet the requirements of this 

 condition that this mouse lays up a 

 goodly stock of food during autumn.' — 



something the jerboa or jumping- 

 mouse, does not do. However this 

 may be, the fact remains that both 

 these rodents are quite sensitive to 

 cold, and hibernate as soon as winter 

 sets in; yet how very differently is this 

 faculty exercised. 



C. C. Abbott. 



The Common Polypody. 



(^Po lyp di It Jii 7 ' II Iga j-c.) 



The common polopody is one of the 

 ferns which it seems must be known to 

 everyJ)ody, by sight at least. It is 

 one of our most abundant species and 

 wherever there is a ledge of rocks is 

 almost .ure to be found. Few ferns 

 love the rocky walls more than this 

 one; other ferns may grow at the base 

 of the cliff but the polypody is content 

 with nothing short of the summit or 

 higher ledges where its matted fronds 

 and root-stocks form the principal veg- 

 etation. So constant is this feature 

 of the fern that one may almost iden- 

 tify it with certainty as far as he can 

 see it. 



The situations in which the ^poly- 

 pody grows are often exposed to con- 

 siderable drouth but the plant is one 

 of the few ferns that can exist in sun- 

 ny places and is able to get along with 

 very little moisture. When the ground 

 about it becomes dry and other ferns 

 are drying it merels curls up its fronds 

 and waits for the rain. In the North- 

 ern United States this fern is found on 

 rocks, only, but in other localities 

 where there is more moisture in the 

 air it leaves the rocks and grows on 

 stone walls, the trunks of trees and 

 even on the roofs of houses. It is 

 usually found in such places in the 



