PREFACE. 



The object of this work is so fully given in the Title- 

 page, that little more remains to be said in the Preface. 



Beginning with the simplest and most natural form 

 of habitation, namely, a burrow in the ground, the work 

 proceeds in the following order : — 2nd, those creatures 

 that suspend their homes in the air ; 3rd, those that are 

 real builders, forming their domiciles of mud, stones, 

 sticks, and similar materials ; 4th, those which make 

 their habitations beneath the surface of the water, 

 whether salt or fresh ; 5 th, those that live socially in 

 communities ; 6th, those which are parasitic upon ani- 

 mals or plants; 7th, those which build on branches. 

 The last chapter treats of miscellanea, or those habita- 

 tions which could not be well classed in either of the 

 preceding groups. 



In all these classes a definite order has been pre- 

 served, the Mammalia having precedence, and being 

 followed in regular order by the other members of the 

 group. Thus, in the first few chapters, which treat of 

 the Burrowers, the following system has been observed : 

 First comes Man, the chief of all the mammalia, and 



