Holomastigotes 

 elongatum . 



Winged male and 

 female (alates) 



Trichonympha 

 agilis /jj^. 



Spirotrichonympha 

 flagellata v , >^ 



Soldier 



Young 

 nymph 



Eggs 



Young 

 nymph 



SYMBIOSIS AMONG ANIMALS 



The flagellates which live within the digestive tract of the termites change wood into 

 soluble carbohydrates. The termite furnishes the protozoans a comfortable shelter 

 and keeps them supplied with small bits of wood — which the termite can break down 

 mechanically, but cannot digest 



p. 180). Very many of such species take practically all the food for a life- 

 time during the larval stage, living the rest of the time on accumulated 

 reserves. 



A third type of intermittent feeding is illustrated by the golden plover. 

 This bird summers in the arctic and then migrates to southern South Amer- 

 ica. It travels 2400 miles in a nonstop flight, on energy from the fat stored 

 within its body. 



The intermittent feeding of animals is not unlike the habits of many 

 plants. In the common annual plants that start from seeds and end in seeds 

 within a few months, there is a long stretch of time during which metabo- 

 lism is at a standstill. The food for the renewal of life in the spring is the 



179 



