CHAPTER VI. 



IDENTIFICATION, 



SO far as this country is now concerned, the differences between 

 the orders represented are so marked that there is hardly any 

 difficulty in at once assigning a mammal to its proper group. If it 

 has no hind legs it must be a cetacean ; if it has wings it must be a 

 bat ; if it has hoofs it must be an ungulate. Practically doubt can 

 only arise in the event of its being a rodent, a carnivore, or an 

 insectivore ; and as a carnivore it can at once be distinguished by 

 its prominent canines, as a rodent by its large incisors and the gap 

 where the canines ought to be. Among the insectivores, the hedge- 

 hog and mole are almost as well known as the cat and the dog, and 

 it is in the case of the shrews alone, as evidenced by the popular 

 name of shrew-mice, that mistake is likely. In short, if we know 

 our shrews, the path of identification is easy. 



The main points in which a shrew differs from a mouse are 

 these. The shrew has a much longer muzzle than the mouse ; in 

 the shrew the tail is hairy, in the mouse it is scaly ; in the shrew it 

 is squarish and straight for some distance, in the mouse it is round 

 and tapers from the root to the tip ; in the shrew the ears are small 

 and lie flat against the head, in the mouse they are large and 

 prominent. But the great differences are in the teeth. In the 

 shrew the teeth are very small and require a magnifying glass tc 

 distinguish them, in the mouse they are fairly large ; in the shrew 

 there are eighteen to twenty in the upper jaw and twelve in the 

 lower, in the mouse there are eight in each of the jaws. Thus the 

 shrew has thirty or thirty-two teeth and the mouse only sixteen ; 

 those of the shrew are continuous, those of the mouse have a large 

 gap in the row and this is filled by the hairy skin ; the mouse has only 

 two incisors, the shrew has more than two ; those of the mouse are 

 flat and chisel edged, those of the shrew are pointed ; in the shrew 

 the canines are much the same as the incisors, the mouse has no 

 canines at all ; the shrew has three premolars, the mouse has no 

 premolars, ; in fact, the only teeth the mouse has are two incisors 

 and six molars, three a side, top and bottom. Of course there are 

 other differences, but these are enough to show that the shrew is an 

 insectivore and the mouse a rodent, which is all we intended to do. 



And now let us take a bat and find out its name. The first things 

 to look for are the leaf-like appendages the nostrils, which, when 

 .present, are the most prominent feature of the head. The bat we 

 have chosen is not one of the horseshoes, and consequently has 

 no nose-lea.f, Clearly, then, its family is Vespertilionidas, as is 



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