110 



NORTH AMERICAN; FAUNA 66 



Type locality. — Lake Drummond, Dismal Swamp, Norfolk County, Va. 



General distribution. — Reported from Chester County, Pennsylvania, south in 

 the Coastal Plain and Piedmont to the lower Cape Fear drainage of southeastern 

 North Carolina. 



Distribution in Maryland. — Eastern Shore, Western Shore, and 

 Piedmont sections. 



Muskrats are especially abundant in the fresh- water and brackish 

 marshes of the Eastern Shore section. The subspecies Tnacrodon inter- 

 grades with 0. z. zibethicus in the Piedmont section and is probably 

 replaced by that subspecies in the Eidge and Valley and Allegheny 

 Mountain sections. 



Distinguishing characteristics. — Teeth 1/1, 0/0, 0/0, 3/3, == 16; 

 tail long and laterally compressed; hind feet partially webbed; ears 

 small and almost hidden in fur; pelage dense, underfur soft and thick, 

 overlaid with long smooth guard hairs; usual coloration a rich brown, 

 with considerable bright russet to red tinge, darker on head, ncse, 

 and back; ^ides grayish brown to russet; underparts considerably 

 lighter, varying from grayish drab to bright cinnamon rufous. 



There is a black color phase of this subspecies which in some Mary- 

 land marshes runs as high as 65 percent of the population (Dozier, 

 19486, p. 393). These animals are not uniformly black, but have a 

 modified agouti pattern shown in the lighter ventral surfaces and on 

 the lower side areas where the hairs are subapically banded with 



Figure 40. — Distribution of Ondatra zibethicus. 



