General Morphology of the Protozoa 43 



vacuome of Opalina is said to serve for the storage of proteins (114). In 

 addition, the vacuome contains volutin in Chilomonas Paramecium (59), 

 Peranema trichophorum (23), Polytoma uvella (219), and species of 

 Euglena (22, 178). 



The neutral-red granules which collect on the food-vacuole in certain 

 ciliates (Fig. 1. 19, E) have been called digestive granules. Prowazek (184) 

 suggested that they enter the food-vacuoles of Paramecium aurelia and 

 participate in digestion. Similar conclusions have been reported for P. 

 caudatum (192), Vorticella (218), and Tetrahymena pyriformis (221). 

 Both Koehring (135) and Dunihue (49), while confirming aggregation 

 at the surface, have denied that the neutral-red granules penetrate the 

 food-vacuole in Paramecium. Such granules apparently get into food- 

 vacuoles of Ichthyophthirins without penetrating a membrane. The gran- 

 ules collect on a freshly formed food-vacuole, a new membrane is de- 

 veloped around the mass, and the original vacuolar membrane then 

 disappears (156). Although no such relationship has been detected in 

 certain other ciliates (75, 78), the behavior of these inclusions in Parame- 

 cium and Ichthyophthirins may justify their designation as digestive 

 granules. 



Osmiophilic inclusions and organelles 



A number of osmiophilic structures and inclusions have been in- 

 terpreted as protozoan Golgi material. The nature of such material is 

 undoubtedly varied, and complete agreement has not been reached in 

 regard to the identity of protozoan Golgi apparatus.- Even a single species 

 has sometimes been credited with two or more kinds of Golgi material. 

 This situation is not surprising because the Golgi techniques are not 

 absolutely specific. Furthermore, selection of the appropriate inclusions 

 is handicapped by the lack of a precise concept of protozoan "Golgi 

 material" and specific criteria for identifying such material.^ 



Protozoan Golgi material apparently was first described as osmiophilic 

 rings and crescents in Monocystis ascidiae (84). Comparable inclusions 

 (Fig. 1. 19, G-I) have been reported subsequently in many species of 

 Mastigophora, Sarcodina, Sporozoa, and Ciliatea. The distribution and 

 relative number of such "Golgi bodies" apparently vary within a species. 

 Golgi material may even disappear in the cyst and arise de novo after 

 excystment, as in Ichthyophthirins (157) and Protoopalina (189). Young 



-This subject has been discussed in several reviews (76, 77, 83, 121, 158, 202, 208). 



^This situation in protozoan cytology merely reflects the unstable position of "Golgi 

 material" in metazoan cytology. Some workers maintain that ". . . the Golgi apparatus 

 is a gross artifact" (176). According to another view, "a tissue lacking the full com- 

 plement of Golgi substance would be unable to function normally" (237). Likewise, 

 the statement that "efforts to demonstrate a Golgi apparatus in living, or fresh, somatic 

 cells have been unsuccessful" (175), may be contrasted with the conclusion that "the 

 Golgi apparatus can be seen in most, and perhaps all, living animal cells" (237). 



