10 POND LIFE 



As this book is not one dealing with marvels of plant life, 

 excepting those few that live in ponds and streams, we must 

 be satisfied with these, which are none the less interesting 

 because they belong to the microscopic kingdom. 



What are plants ? and how do they differ from animals ? 

 The reader will find that many of the pond life plants have 

 one or more animal characters, while certain animals have 

 plant-like characteristics. Plants and animals vary from each 

 other as follows : 



Plant Animal 



Has greatest surface and least Greatest bulk and least surface. 



bulk. 



Has no digestive system. Has a complex digestive system. 



Is unable to move. Has free movement. 



Has an external skeleton (cellu- Has an internal skeleton. 



lose). 

 Lives on simple but highly oxi- Lives on complex compounds. 



dised compounds. 

 Contains chlorophyll (green Does not contain chlorophyll. 



colouring matter). 



In the case of the "higher" plants very few have animal 

 characteristics, but many of the algae and certain microscopic 

 plants behave in a very similar way to animals. 



Unfortunately for man, the three kingdoms, animal, vege- 

 table, and mineral, were allotted before science had made much 

 headway, and so it stands to reason that there are many things 

 typically members of none of the above kingdoms. When 

 such are classified as plants a feeling of utter astonishment is 

 experienced by those uninitiated in the peculiarities of scien- 

 tific nomenclature. 



To the average mind the majority of these dubious plants 

 are more characteristically animals, but it must be remembered 

 that the ordinary non-scientist does not usually value all the 

 points, but forms his opinion by the things which are most 

 noticeable. It is interesting to know that the appearance of 

 a Desmid moving gracefully, as if drawn by some powerful 

 magnet, across the slide, gives even the average mycologist an 

 impression of animal, although he is fully aware that what he 

 sees is really a plant. Little can it be wondered at, therefore, 

 that the non-hardened mycologist is fully convinced that many 

 plants are " animals," and that the scientist who named them 

 plants was utterly mistaken. 



A single-celled plant, so minute that several hundreds could 

 be placed in a pin-prick without crushing ; an architect and 



