1048 Observations on the Muskrat. [ November, 
vegetation, even of the roots, for some distance. The house was 
thatched very nicely with weeds and sedge. The ground plan 
was oval in outline, four feet six inches wide and six feet three 
inches long. On the land side the house was two feet six inches 
high, and on the water side three feet four inches. The whole 
presented the appearance, in miniature, of an oblong hay rick. 
The inside was quite irregular. Measurements at the bottom of 
the chamber showed the greatest length to be twenty-two inches, 
the least sixteen inches, with an average width of twelve inches. 
The greatest height, measuring from the bottom of the stream, 
was one foot, Six inches from the bottom a shelf was found 
running from the left of the entrance and above the top of the 
water. This shelf was twelve inches long and eight inches wide, 
and ranged from six to eight inches in height. It was arched 
over very neatly with drift and coarse weeds. At a point farthest 
from the center of the chamber, immediately over the shelf, was 
a passage leading upwards toward the side of the house. While 
it did not penetrate the wall, it passed through the more compact 
portion and enabled the inmates to obtain air. Entrance was had 
through a covered way from and beneath the water without to 
the center of the house, where it terminated in a mass of fine 
grass and mud, through which was a funnel-shaped opening to 
the interior. This house was completely destroyed; within a 
week after its destruction the muskrats had erected a new home 
upon the site of the old one. In securing material for this they 
had used the remains of the ruined house, and had cleared a 
much larger space of ground of its withered vegetation. In out- 
line the new house resembled the old one very much, but it was 
of nearly double the size of the ruined structure. There are 
peculiarities in the shape of many houses, but that which I have 
described appears typical in form and in interior arrangement of 
these structures in this vicinity. Some of these houses are built 
at a time when the water is low, and as the fall rains swell the 
streams the rats are compelled to ,reconstruct their buildings, 
raising the top above the highest level of the water. I knew a 
muskrat to try this plan last year. It built its house within the 
o banks of an ice-pond which was almost dry; as the water was 
turned on, late in the fall, the owner tried, by making the house 
higher, to keep a portion of the structure above the encroaching 
ter. An increase in altitude of six feet was too mych for the 
