PROTOZOA 



27 



Entameba buccalis {gingivalis) , found in the mouth around carious 

 teeth, is considered one of the causes of Pyorrhoea alveolarisJ^ 



Class 2. Mastigophora (Flagellates). Type of Group — Eu- 

 glena. — Certain intermediate forms called Mastigamebae (Fig. 7) 



...Girdle 

 -- Tooth 



!l7"ii Longitudinal 



Flagellum 



.Tentacle 



Fig. 6. Noctiluca scintillans, postero- ventral view. (Courtesy of C. A. Kofoid.) 



have not only the changeable shape and pseudopodia of the ameba, 

 but are provided with a flagellum in addition. There is apparently a 

 direct evolution from the pseudo- / 



podium to the flagellum. 



The true flagellates may have 

 one or more flagella. Some- 

 times one flagellum is used for 

 locomotion and another as an 

 anchor. Some forms have cellu- 

 lose tests and some are without 

 any shell or case. One group of 

 marine flagellates have siliceous 

 skeletons similar to those of the 

 Radiolaria. Reproduction is by 

 simple longitudinal division. 



' FlocjeUum 



„V(/> P^eudopodi-um 



Fig. 7. 



Mastigameba aspera. (Calkins. 

 After F. E. Schultze.) 



Sometimes encystment occurs. 



Euglena is a green flagellate found in fresh water associated with 



3 Kofoid, C. A. 1929. The protozoa of the human mouth. Jour, of Paras., vol. 

 15, pp. 1 51-174. 



