PHYLUM PROTOZOA 



35 



mimicry of the collared cells of sponges (Fig. 50 B) that some zoolo- 

 gists have seen a possible origin of the sponges from these 

 choanoflagellates. 



Chilomastix (Fig. 20), Giardia (Fig. 21), and Trichomonas 

 (Fig. 22) are genera which have species living very commonly as 

 intestinal parasites of man and represent unusual degree of 

 development of a neuromotor apparatus. 



Blepharoplash 

 Nucleus 



Fig. 20. 



-Chilomastix mesnili (Wenyon). A, active stage; B, encysted. 

 Kofoid and Swezy). 



{After 



Flagellates living in the gut of termites represent the most 

 highly specialized members of the Mastigophora and the most 

 bizarre types of protozoan structure. Their bodies are so closely 

 set with fiagella that they were originally considered as ciliates. 

 In the bodies of their hosts, according to the discoveries of 

 L. R. Cleveland (1923), they digest the wood eaten by the termites. 

 The symbiotic interdependence between the flagellates and their 

 host is revealed by the fact that the Protozoa die if the termites 

 are deprived of wood and the termites are unable to subsist on 

 wood diet if freed of the flagellates. Trichonympha, Teretonym- 

 pha, and Stephanonympha are representative genera of these 



