153 



of aquatic plants. It seeks its food under the ice, and evidently carries 

 it to its burrows. No large stores are observed in its burrows, however, 

 but only roots recently carried in. The summer food consists of leaves of 

 various aquatic plants, and different species of river muscles. Every one 

 at all familiar with the shallows of our streams, will recall the immense 

 heaps of muscle shells, often a bushel or more, by the side of some large 

 stone or log, midway perhaps of the river, and furnishing easy collecting 

 grounds for the conchologist. These are the "oyster restaurants" of the 

 Muskrat. Collecting the muscles from the river bottom, the Muskrat 

 mounts the log or stone, sits up on its haunches like a Squirrel, and 

 opens the shell with its strong incisor teeth, as neatly as a Squirrel 

 opens a nut. Most of the shells are left with the ligament intact. Mr. 

 Kennicott has found massive shells, like those of Unio plicalus, left un- 

 opened, or with the valves gnawed apart at the back. 



The Muskrat is pugnacious, fights when captured, and the males often 

 have fierce battles among themselves. The Mink is its worst enemy, en- 

 tering its houses and burrows, and pursuing it in the water. 



From five to seven young are produced in April or May. 



Muskrats are seldom injurious to crops ; sometimes they take to vegeta- 

 ble gardens, showing a commendable weakness for parsnips and muskmel- 

 lons. They are sometimes destructive to growing corn, which they cut 

 off and sink into the water, probably to eat at their leisure. With the 

 exception of the moUusks already referred to, and the occasional eating 

 of a dead fish, they do not depart from a vegetable diet. 



Their depredations on canal banks, mill dams, and ice ponds are well 

 known. Along the line of the Illinois and Michigan canal, the "canal 

 walkers " are compelled to keep a sharp eye to the Muskrats, lest they 

 burrow through the bank, and trappers, with their boats, are passed 

 through the locks and given the right of way along the tow-path. 



Mr. Kennicott states that " hunters and trappers consider the hind- 

 quarters cf the Muskrat very palatable, when roasted on coals ; and they, 

 as well as the Indian, esteem the tail a great delicacy. 



FAMILY HYSTRICID^. 



The American Porcupines, sub-family Syneiherinx, differ from the Old 

 World Porcupines, sub-family Hystricinse, in the form of skull; in having 

 the clavicles perfect, the tail (except in Erethizon) more or less prehen- 

 sile, the molar teeth fully rooted ; in not having five toes to all the feet 

 (usually four, both before and behind) ; in the tuberculated, instead of 

 smooth soles; in the upper lip being undivided by a vertical groove; 



