48 



BOYS AND GIKLS IN BIOLOGY. 



very well in the duck-weed (Fig. 36), a tiny plant 

 which floats on the surface of ponds. The food which 

 they take up is made of water, ammonia, or hartshorn, 

 and mineral matters ; all the different parts of the 



Fig. 37. 



Duck-Weed. Dotted Ducts, or Tubes, that 



cakry Juices to the Leaves. 



plant, its leaves and flowers, are made by these simple 

 things. The little sponges, or spongioles, have such • 

 dainty appetites, they know just what to sip, and if they 

 cannot get it close at hand they search till they find 



