Genus Fir.EU. — This small genus comprises but one species, nnil is of 

 amphibious and partially nocturnal habits. It is placed by Colonel Hamilton 

 Smith next to the beaver in the division of the Arvieolidic. It is dicstin- 

 guished for its strong, musky odor. 



F. Zcbrlldcxa. — Tiic Muskrat. This species was formerly very abun- 

 dant throughout the whole of Xorth America. It is of a brown color, darker 

 in winter, with a predominant gray hue ; has a long compressed tail, and is 

 nearly three times the size of the common rat, which it resembles in form. 

 Although it retires as human industry and enterprise clear away the forests, 

 and cover the banks of the rivers and streams with mills and manufactories, 

 it may still be found in considerable numbers in many parts of the country 

 Mhich, thus far, ha\-e been left undisturbed. In the early morning and the 

 evening twilight we have often seen it j)ursuing its avocations, and s[)orting 

 itself in the secpicstcred streams of Maine, and also in some of the more 

 retired parts of Massachusetts. In the Middle and Western States it is still 

 sufnciently numerous to be an oliject of eager pursuit to those who are 

 engaged in the fin- trade. It feeds on certain kinds of grasses, aquatic, 

 roots, sucli as the ling and lilv ; and when it has a taste fir animal food, it 

 will not disdain a fish, and is skilful in seizing and dressing for its use sev- 

 eral kinds of Crustacea. Its houses are curious specimens of architecture. 

 They are built on, or rather under, the banks of streams or ponds, and gen- 

 erally lia\'e two or thrc(! enlrances, one from the land, and the others be- j 

 neath the water. They consist of two parts ; an outer apartment, or court, 

 and an interior chamber, the latter furnished with dried grass and leaves, to 

 which the animal retires for repose, and where the female rears her young, 

 M'hich consist of from live to eight, or even nine, at a birth. 



The muskrat, being amphibious, sjiends a considerable portion of its time 

 in the water. Its apparatus for breathing, which enables it to remain for a 

 length of time beneath the surface, is similar to that of the amphibians here- 

 tofore described. A\ hen the ponds and streams are frozen, it keeps air-holes 

 ojicn in the ice, after the manner of the seals. 



In portions of the country whicii are sparsely inhabited, it will make short 

 nightly excursions inland, in (juest of sweet succulent roots, like the parsnip, 

 beds of which, in the spring, wo ha\'e seen quite ravaged and destroyed. 

 This plant appears to be ])articularly agreeable to its taste, and we have 

 often used it as a bait in trapping the animal. Hunters employ not only 

 traps, but snares and spears in their war upon nuiskrats, and it is probable 

 that the persecuted race will wholly disappear <;re long from the vicinage of 

 civilized lil'c. 



Hystuicixa. — This family comprises rodents with imperfect clavicles, 

 many of them more or less armed with spines. In the first division is 



