162 RODENT WATER TRESPASSERS. 



closed over them; and the mouth is, in consequence, 

 perpetually open. 



This would not matter very much in a terrestrial 

 quadruped, but as the Coypu is semi-aquatic, passes 

 much of its time in the water, and also swims with its 

 body almost entirely submerged, the water would run 

 down its throat as it swims, and thus prevent it from 

 swimming for any length of time. On opening the 

 mouth, however, a most curious structure is seen. 

 The palate is modified into a soft cushion-like projec- 

 tion, which is covered with hair, and which passes 

 behind the teeth, so as to close the aperture. 



Nor is this all. In most animals the glottis, or 

 entrance to the wind-pipe, opens into the back of the 

 mouth; although, as with mankind, it can be connected 

 at will with the nostrils, so as to allow of respiration 

 through them. The Coypu,. however, has no choice in 

 the matter ; the glottis opening into the cavity which 

 leads to the nostrils, so that it could not breathe 

 through its mouth even if it wished. 



Thus, there is a double protection to the lungs 

 from being filled with water i the projecting palate 

 forming the first line of defence, and the structure of 

 the glottis the second. If the water were to flow 

 down the throat only, and find its way into the 

 stomach, much inconvenience would ensue, but that 

 is all ; whereas, life would be endangered if water 

 were to find its way into the lungs. 



We see, therefore, that the stomach is protected 

 from water by a single line of defence, namely, the 

 projecting palate ; and no great harm would happen 

 even if a drop or two of water did force their way 



