56 Journal OF THE Mitchell Society [October 



in color. Their pointed snouts and mole-like fur are characteristic. 



Of the introduced species the two large rats are apt to be confused, 

 but weight seems to be diagnostic as the heaviest roof rat I have 

 weighed tipped the scales at only 5 1/2 ounces while the smallest 

 adult wharf rat weighed over 7, and the largest 21 ozs, with an aver- 

 age of not less than 11 or 12 ozs. The tails, too, differ in length, 

 the tail of the roof rat when stretched forward over the back reaching 

 well beyond the nose, while that of the wharf rat does not come much 

 further forward than the ears. Roof rats appear to be more diurnal 

 in habit, and usually seek to escape if possible by climbing upwards 

 while a wharf rat instinctively goes down. ISTeither species seems 

 to occur in the fields in this locality. 



The house mouse occurs both in and around human habitations 

 and in fields far from the haunts of man. It is not likely to be con- 

 fused with anything else but the harvest mouse, which, however, has 

 much softer fur, a blunter snout, and more distinctly whitish under- 

 parts. Fortunately, too, it has a structural difference in that there 

 is a groove down the anterior face of its upper incisors, which is ab- 

 sent in the house mouse. 



Of the native species the commonest is the whitefooted or deer 

 mouse, which is not likely to be confused with any other of our Ra- 

 leigh species except the red mouse from which it differs totally in 

 habits, being terrestrial while the other is an arboreal form. The 

 deer mouse is tawny on the sides with a darker area on the back, the 

 color of the sides and the white of the underparts abruptly distinct, 

 not shading into one another, tail bicolored, white below, tawny above. 

 This species is found everywhere in fields and in woodlands, often 

 forming fifty per cent of the mice and shrews caught when trapping. 

 It seems to nest mostly in rotten stumps or logs either above or below 

 ground. 



The species most closely resembling the deer mouse is the red or 

 golden mouse which differs from all the rest of our rats and mice by 

 its arboreal habits. This is a species of low grounds and thickets 

 along streams, building its nests in small trees, reeds or thickets often 

 as high as fifteen feet from the ground. Usually an inspection of 

 the nests will tell if the mouse or mice are at home, as the hole is 

 usually open when they are away, and closed when the inmates are 



