168 THE BOOK OF NATURE STUDY 



many animals, how is it that others can live and thrive in it ? 

 We have suggested above an answer for one mud-haunting 

 animal, but there are many others which should be similarly 

 studied. 



We have given in this article scientific names and references 

 which will enable the teacher well placed with regard to libraries 

 to name or further study his finds, because there are a consider- 

 able number of persons who are strongly attracted towards system- 

 atic work, but it must not be supposed that this is the only kind 

 of work which can be done on the shore. The study of adapta- 

 tion, of the fitness of animals to their surroundings, and the 

 problems as to how this fitness has originated, and how it is 

 maintained, are problems which appeal to many who are totally 

 uninterested in systematic work. An attempt has been made 

 above to show how these problems may be approached, and how 

 the aquarium may be used to aid their investigation. 



BOOKS OF REFERENCE. In the list of books relating to the freshwater animals, 

 mention has been made of some books dealing also with marine animals. Of 

 other books the author's Life by the Sea-shore (London, 1901) may be named ; 

 it includes references. A very cheap and useful little book is Wood's Common 

 Objects of the Sea-shore (London, 1864). In identifying the members of the 

 different groups, in addition to the books named on p. 126, the following may be 

 used : Hincks' British Hyroid Zoophytes (London, 1868), Gosse's History of the 

 British Sea- Anemones (London, 1860), Catalogue of Echinoderms in the British 

 Museum by Jeffrey Bell (London, 1892), Bell's History of the British Stalked-eyed 

 Crustacea (London, 1853). 



