218 THE BOOK OF NATURE STUDY 



But, apart from some extinct reptiles, the only animals with 

 the power of true flight are insects, birds, and bats. From some 

 old tower or from a barn it may be possible to get some bats 

 certainly the quaintest of mammals. One should demonstrate 

 the structure of the wing the skin stretched between the long 

 spider-like fingers, the backward turned knee, the sharp cusps of 

 the cheek-teeth, and so on. As a climax of aerial life one might 

 perhaps take the swift (Cypselus apus\\vhich hardlyrests in summer 

 from dawn to nightfall in its dashing flight. If a specimen is 

 procurable it is easy to show that the great length of the wings 

 and the small size of the feet (with their four toes turned forwards), 

 makes walking very difficult, and if a swallow can be got for com- 

 parison it is very well worth while spending time in showing that, 

 in spite of some resemblance in habit and in general appear- 

 ance, the two birds are not related. The swift may also be 

 taken as a good example of a summer visitor arriving towards 

 the end of April, and usually leaving by the end of August on 

 its journey to African winter quarters. But it is well not to 

 overload with information ; let the pupils get a good impression 

 of the swift in its mastery of the air. " The wild screeching note 

 is sometimes quite startling, when uttered by a flock of birds 

 sweeping by at lightning speed, and often in the worst of weather, 

 for the swift seems to revel in the storm " (Howard Saunders). 



Summary. There are six great haunts of life the shore, 

 the open sea, the deep sea, the fresh waters, the dry land, and 

 the air. Each of these haunts has its peculiar conditions and its 

 characteristic fauna, and it is to some extent possible to inter- 

 pret the peculiarities in the animals as adaptations to their 

 several haunts. 



More detailed Study. Much has been done in recent years 

 in the study of " plant associations" or "characteristic vegeta- 

 tions/' the assemblages of similar plants which occur in 

 similar areas. Wood and heath, sand-dunes and shore, 

 moor and bog, and so on, are more or less distinctly 

 marked, wherever they occur, by analogous plants char- 

 acteristic of each environment. This is an interesting and 

 educative kind of study, and it should be pursued in regard to 

 animals. In the foregoing pages we have suggested a number 



