ir 



PHYLUM PROTOZOA 



105 



As to the Ciliata, Multicilia and LopJiomonas (Fig. 72, 12 and 13) 

 appear to indicate the derivation of the order from the Flagellate 

 type, since their cilia are long and flagellum-like ; but the evidence 

 is not strong and no other is at hand. The derivation of the Tenta- 

 culifera from a ciliate type appears to be clear. The Tentaculifera 

 and the hypotrichous Ciliata are undoubtedly the highest develop- 

 ment of the Protozoan series, since they show a degree of 

 differentiation attained nowhere else by a single cell. 



Radiolaria 

 Foraminifera 



Lobosa 



Mycetozoa 



Dinoflagellata 



Cystoflagellata 



Heliozoa 



Tentaculifera 



Ciliata 



-Sporozoa 

 FIG. 78. Diagram showing the mutual relationships of the chief groups of Protozoa. 



The Mycetozoa appear to have been derived from the common 

 amoeboid-flagellate stock, since they are all predominantly amce- 

 boid in the adult condition, flagellate when young. The Sporozoa 

 probably had a similar origin, but the characters of this class have 

 evidently been profoundly modified in accordance with their 

 parasitic mode of life. 



The diagram above is an attempt to express these relationships 

 in a graphic form. 



