MAMMALS 255 



of the nose and the soles of the feet. Where are the 

 nostrils placed ? What are the large leaf-like expansions, 

 called pinna;, situated just back of the eyes ? Pull open 

 the mouth and note the large incisor teeth on the upper 

 and lower jaws. Cut one corner of the mouth back and 

 observe the large flat-topped molar teeth on both jaws. 

 How does the attachment of the large fleshy tongue differ 

 from the condition in the toad .' The toad's tongue is for 

 snapping up insects, whereas in the mouse this organ 

 serves to move food about in the mouth. On the tongue 

 are numerous small taste-papilla;. Notice the long hairs, 

 " feelers," on each side of the nose. Note the similarity 

 between the front paws and our own hands ; each has 

 four fingers, with a small rudimentary thumb on the inner 

 side of the paw. How does the hind foot of the mouse 

 differ from the foot of man } Posteriorly the body is 

 terminated by a long tail. 



The house-mouse is not a native of North America, 

 but was introduced from Europe, to which, in turn, 

 it came from Asia, its original habitat. The mouse 

 came to this country in the vessels of early explorers. 

 Similarly the brown and black rats, now so abundant all 

 over North America, and members of the same genus as 

 the mouse, were introduced from Europe. Accompany- 

 ing man in his travels the mouse has spread from Asia 

 until it is now to be found over the whole world. 



The habits of mice are well known, their fondness for 

 living in our homes and outbuildings making them familiar 

 acquaintances. Their food is varied; they seem to thrive 

 best, however, on a vegetable diet. Grains and nuts are 

 favorite foods. The house-cat is their greatest enemy, 

 but man takes advantage of their instinct to go into holes 

 by constructing traps with funnel or tunnel entrances, 

 which, baited with cheese or other favorite food, are 

 fatally attractive. In climbing, mice are aided by the 



