A NEW MUSK RAT. 77 



species of musk-rat, which I have named Fiber 

 osoyoosensis. 



The Musk Rat, which I believe is the well- 

 known Fiber zibethicus of Cuvier, makes its holes 

 in the clayey banks of streams and pools where 

 the water runs slowly. The entrance is always 

 below the surface, the hole dug up in a slanting 

 direction above the water-level. A stage or flat 

 place is cleared, which constitutes the dining-, 

 drawing-, and bed-room ; leading to the entrance 

 of this mansion are a number of open cuttings, 

 running in all directions, dug in the mud at the 

 bottom of the water. When foraging about, as the 

 musk rat usually does about twilight, if alarmed, 

 it dives at once into one of these cuttings, and, 

 rushing rapidly through, stirs up the mud, thus 

 fouling the water, and completely and effectually 

 concealing itself. 



The other Musk Rat, which I call Fiber oso- 

 yoosensis, differs in size, colour, and structure, 

 but particularly in habits, from the preceding. 

 This fellow chooses as his haunt a clear pond 

 or lake, and in water from three to four feet deep 

 constructs a house of bulrushes, in form conical, 

 built up from the bottom how I am at a loss to 

 imagine the roof cleverly arched over into a 

 domed shape, and raised about a foot above the 



