MORPHOLOGY AND PHYSIOLOGY 



23 



ture. Closely related to this is the parabasal body, or apparatus, 

 found in certain Mastigophora, such as Polymastigida and Hy- 

 permastigida. It occurs in a close association with the nucleus. 

 Its function is not well understood, but in some forms it appears 

 to be a cell-organ of protection for the nucleus, while in others 

 it may be a storing organelle of material used by the kinetic 

 cell-organs. 



The Cytoplasm 



The bulk of the body of a protozoan is made up of the cyto- 

 plasm, which is almost always colorless. Certain Protozoa 

 encased in a test, or lorica, may show coloration due to the color 



Flagellum 



Undulating 

 membrane 



Nucleus 



Basal granule 

 Blepharoplast 



Anterior flagellum 

 Basal granule 



Blepharoplast 

 Rhizoplast 

 Nucleus 

 Parabasal body 



Posterior flagellum 



Diagrams of two flagellates showing their structures. 



a. Trypanosoma brucei 



b. Prowazekella lacertae (After Kiihn). 



of the latter. Chromatophore-bearing forms, of course, appear 

 colored, but the cytoplasm itself is usually colorless. There are, 

 however, a few exceptions. One of them is the heterotrichous 

 ciliate, Blepharisma lateritia (Fig. 160), which is frequently 

 colored pink. Arcichovskij found a special pigment in this 

 protozoan and called it zoopurpurin. 



The extent and nature of the cytoplasmic dififerentiation 

 differs greatly among various groups. In a number of forms the 

 cytoplasm is differentiated into two parts: ectoplasm and endo- 



