46 PROTOZOOLOGY 



risma are rose- or purple-colored. The color is due to the presence of 

 zoopurpurin (Arcichovskij, 1905) which is lodged in numerous gran- 

 ules present in the ectoplasm. This pigment is soluble in alcohol, 

 ether or acetone, and is destroyed by strong light (Giese, 1938). 

 Weisz (1950) maintains that both pigment granules are chondrio- 

 somes, and in Stentor, cytochrome oxidase appears to be localized in 

 the pigment granules. 



The extent and nature of the cytoplasmic differentiation differ 

 greatly among various groups. In the majority of Protozoa, the 

 cytoplasm is differentiated into the ectoplasm and the endoplasm. 

 The ectoplasm is the cortical zone which is hyaline and homogeneous 

 in Sarcodina and Sporozoa. In the Ciliophora it is a permanent and 

 distinct part of the body and contains several organelles. The endo- 

 plasm is more voluminous and fluid. It is granulated or alveolated 

 and contains various organellae. While the alveolated cytoplasm is 

 normal in forms such as the members of Heliozoa and Radiolaria, in 

 other cases the alveolation of normally granulated or vacuolated 

 cytoplasm indicates invariably the beginning of degeneration of the 

 protozoan body. In Amoeba and other Sarcodina, the "hyaline cap" 

 and "layer" (Mast) make up the ectoplasm, and the "plasmasol" 

 and "plamagel" (Mast) compose the endoplasm (Fig. 46). 



In numerous Sarcodina and certain Mastigophora, the body 

 surface is naked and not protected by any form-giving organella. 

 However, the surface layer is not only elastic, but solid, and there- 

 fore the name plasma-membrane may be applied to it. Such forms 

 are capable of undergoing amoeboid movement by formation of 

 pseudopodia and by continuous change of form due to the movement 

 of the cytoplasm which is more fluid. However, the majority of 

 Protozoa possess a characteristic and constant body form due to the 

 development of a special envelope, the pellicle. In Amoeba striata, 

 A. verrucosa (Howland, 1924), Pelomyxa carolinensis, P. illinoisensis 

 (Kudo, 1946, 1951), etc., there is a distinct pellicle. The same is true 

 with some flagellates, such as certain species of Euglena, Peranema, 

 and Astasia, in which it is elastic and expansible so that the organ- 

 isms show a great deal of plasticity. 



The pellicle of a ciliate is much thicker and more definite, and 

 often variously ridged or sculptured. In many, linear furrows and 

 ridges run longitudinally, obliquely, or spirally; and, in others, the 

 ridges are combined with hexagonal or rectangular depressed areas. 

 Still in others, such as Coleps, elevated platelets are arranged paral- 

 lel to the longitudinal axis of the body. In certain peritrichous 

 ciliates, such as Vorticella monilata, Carchesium granulatum, etc., 



