ZOOFLAGELLATES 143 



membrane. No information on pinocytosis or phagocytosis has 

 been obtained. 



Similarities in the structure of the flagella, the kinetoplast, the 

 pellicle, and the "cytostomal" tube where this occurs all suggest 

 that the trypanosomes are closely related to the bodonids. Highly 

 specialized physiologically for their symbiotic mode of life, they 

 seem to have undergone minimal structural modifications. Of 

 the various trypanosomes and the two bodonids investigated, the 

 ubiquitous free-living Bodo, with its complex anterior fibrillar 

 pattern, appears the least simple. 



Certain similarities of bodonids to euglenoid flagellates may 

 be mentioned: the pellicular fiber system, the accessory rod 

 within the flagellar membrane as in Veranema, the reservoir 

 (circumflagellar depression) with its system of fibrils arising from 

 the kinetosomes. But it would be unwise at this stage to conclude 

 that these resemblances are more than coincidental. 



Superorder Metamonadica 



The flagellates grouped by Grasse (1952) in the Superorder 

 Metamonadica include those formerly placed in the orders Poly- 

 mastigida, Trichomonadida, and Hypermastigida. The poly- 

 mastigote and hypermastigote groupings clearly are artificial and 

 Grasse, elevating several lower categories to ordinal rank, 

 includes seven orders in the superorder. They are almost exclu- 

 sively symbiotic, and several orders of them are known only from 

 the guts of termites and wood-eating roaches. Unlike many 

 animals of all phyla whose adaptations to symbiotic life have 

 included general morphological simplifications and, particularly, 

 reduction of locomotor organelles, these higher zooflagellates 

 have indulged in a profligate elaboration of structure. A constel- 

 lation of curious organelles, with additions and omissions, runs 

 like a theme with variations through the whole assemblage. 

 Prominent among these are the axostyle, a rod of varying thickness 

 occupying an axial position in the body; and the parabasal 

 apparatus, multiplied and embellished in a spectacular array of 

 patterns. A characteristic set of flagella and associated organelles 

 is known as a mastigont, and polymerization of mastigonts has 

 led to series of increasingly elaborate morphological types, 

 especially well demonstrated in the Order Trichomonadida 



