210 CURIOUS HOMES AND THEIR TENANTS. 



can tell, for their teeth are not superior in hardness 

 to those of other animals ; certainly not nearly as hard 

 as the rocks into which they burrow. The hole which 

 the sea urchin forms in stone is large enough to allow 

 him to move about, but not to come out very easily ; 

 indeed, he adheres so firmly with his suckers to the 

 cavity as not to be easily forced to quit his hold. 



A NEST IN A WATERFALL. 



AMERICAN DIPPERS. 



These little birds, which are in reality thrushes, 

 combine, says Dr. Cooper, " the form of a sandpiper, 

 the song of a canary, and the aquatic habits of the 

 duck." 



Although its feet are not webbed, the dipper is in 

 some respects more of a water bird than is a duck, 

 for in search of its food, which consists almost alto- 

 gether of water insects, it descends to a depth of sev- 

 eral feet, walking about on the bottom and flying 

 beneath as easily as it does above the surface of the 

 mountain streams it frequents. 



The dense, thick plumage of the dipper, unlike 

 that of any other land bird, is furnished with an un- 

 dergrowth of downy feathers. While under the 

 water the coat of the dipper, through which no damp- 

 ness can penetrate, shines like silver, on account of 

 the air bubbles adhering to it. 



