170 



THE LOWEST ORGANISMS AND THE CELL 



204. The flagellates. 1 The flagellates (Flagellata) are aquatic, 

 motile forms, either one-celled or consisting of colonies of cells 

 held together in a common gelatinous secretion. The individual 



FIG. 172. Two flagellate forms 



A, Euglena, the motile cell shown above, with its cilium and pigment spot at the 

 forward end, the process of reproduction by simple division while in a resting 

 condition being illustrated below; B, Uroglena Americana, a large colonial 

 flagellate. B, adapted after Moore 



cells are provided with one, two, or sometimes more delicate 

 hair-like appendages called cilia (singular, cilium, meaning an 

 eyelash), which move rapidly in the water and are organs of 

 locomotion. Some forms have chromatophores and can therefore 

 manufacture their own food, while others are colorless and take 

 their food in animal fashion through a funnel-like depression into 



1 The best account of the flagellates will be found in Engler and Prantl, 

 Die Naturlichen Pflanzenfamilien. 



