PHYTOFLAGELLATES 133 



The external morphology of flagella among the phytoflagellates 

 is highly variable and would seem to be the result of opportunistic 

 development in each group of mechanisms to increase efficiency. 

 Internally, the morphology of the flagellar apparatus is fairly 

 consistent throughout the phytoflagellates; the occurrence of 

 accessory fibers leading from the kinetosome, in the form of either 

 tubular filaments or striated roots, is widespread if not universal 

 and foreshadows the much more complex development of such 

 patterns in zooflagellates and ciliates. The existence of true 

 rhizoplasts is confirmed in both phytomonads and chrysomonads, 

 and their behavior in dividing cells needs to be analyzed. Polariza- 

 tion of the cell is conspicuously related to the location of the 

 kinetosome in all flagellates, and extends to organelles with no 

 obvious role in locomotor activities. 



Phagotrophy occurs in probably all phytoflagellate groups, but 

 no new information on the structures involved is available except 

 for the highly specialized mouth of Peranema. Many phyto- 

 flagellates are markedly ameboid, some chrysomonads producing 

 fine filose as well as lobose pseudopodia; no observations of these 

 have been reported. Except in the euglenoids, cell membranes 

 are uncomplicated. 



