24 FEEDING 



superficial area comparable to that which the trunk, boughs 

 and leaves present to the air. 



Animals, on the contrary, have to seek their own food supply 

 where they can find it. Thus they have a compact shape 

 which facilitates movement, and they have a stomach and 

 alimentary canal to digest and absorb the food when caught 

 and eaten. Further, they often have to fight for their prey, 

 which usually resents being caught and eaten. " Get animal 

 est tres mediant, quand on I'attaque il se defend" is pretty 

 well true of them all ; thus they have developed organs for 

 locomotion, claws and teeth and poison glands for defeating 

 their prey, paws and hands for grasping it, mouth and stomach 

 and alimentary canal for digesting it. 



Parasites 



There are, however, certain animals which do live sur- 

 rounded by their food in solution. Parasites such as tape- 

 worms, Cestoda, and the thorny-headed roundworms, Acan- 

 THOCEPHALA, which livc in and on the nutritious juices of 

 the alimentary canal of Vertebrates, have lost their mouth 

 and intestine and absorb through their skins the more or less 

 digested food of their host. The intestine of a Vertebrate 

 is not an attractive abode, but even a tapeworm must have 

 some place it can call a home. 



We have seen that the great differences in the shape of the 

 bodies of plants and animals are due to the different nature 

 of their food. Plants can absorb their food in simple chemicals 

 from the surrounding air, water and earth. Hence they 

 remain stationary and do not move about. They have not 

 to go and seek their food ; the pleasure of the chase is denied 

 them. Their food must be intolerably monotonous and 

 extremely insipid — that which is derived from the air is for 

 the most part just flat soda-water with the "sparkle" left 

 out. Yet one hears no complaint. On the other hand, animals 

 have to seek for their food wherever they can find it. As a 

 rule, larger animals live on smaller animals or on plants and 

 the higher animals live upon the lower animals or upon plants, 

 but ultimately they are dependent on unicellular organisms. 



Library 

 N. C. State ColleD-e 



