\ \ ' i i If 



^ip 



Fig. 77. — Heliosph^ra. (After Hertwig. 



CHAPTER V 

 THE FLOATING ANIMALS 



BY THE EDITOR AND E. T. BROWNE 



To those animals and plants which float in the sea, 

 whether at the surface or in deep water, the term 

 " Plankton " is applied for brevity ;* they are con- 

 trasted with the creatures which crawl upon, or are 

 fixed to, the bottom. In modern usage, Plankton is 

 generally taken to include even powerful swimmers, 

 such as fish and cuttle-fish, as well as helpless and 

 minute organisms. The Animal Plankton alone forms 

 the subject of this chapter. Both figures and text give 

 only sufficient detail to help the beginner in finding 



* Plankton, from a Greek word meaning " that which 

 is drifted," the organisms driven about by the wind, tide, 

 and current. 



162 



