136 CYTOPLASMIC INCLUSIONS 



there has been no clear case of division described — all the evidence indi- 

 cates a de novo origin. 



Small homogeneous spherules are the commonest type of segregation 

 body and they are found in all classes of Protozoa. There are often more 

 than one group in a single individual, as shown by differences in size 

 (Bush, 1934) or differences in localization (Finley, 1934). Complex 

 bodies similar to those found by Kedrowsky in Opalina have been found 

 in flagellates from termites (Kirby, 1932). In some cases such complex 



Figure 38. Segregation granule (refractive body) of Amoeba proteus in successive 

 stages of resorption. (From Mast and Doyle, 1935.) A, normal body; B-F, stages in 

 resorption, optical sections ; D, surface view. Outer layer cross-hatched, shell black, 

 vacuole in outline. 



bodies may be the result of precipitation of dyes or other materials in 

 an aqueous vacuole, but in the cases of the denser granules entirely^ 

 different methods show the duplex structure. In the refractive bodies 

 of Amoeba (Fig. 38), microchemical tests show that the duplex struc- 

 ture represents an actual difference in composition (Mast and Doyle, 

 1935a). 



The segregation granules are most often scattered at random through- 

 out the endoplasm (Hall and his associates, 1929 on), but occasionally 

 are more definitely localized. In Trypanosoma. (Figs. 36, 37) they are 

 concentrated around the blepharoplast (Nigrelli, 1929), in the Ophry- 

 oscolecidae they are most common in the operculum and spines (Mac- 

 Lennan, 1933), and in Lechriopyla a marked concentration is found just 

 under the pellicle (Lynch, 1930). In Vorticella a group of discrete 

 globular inclusions is found scattered in the cytoplasm, and another group 

 is found in the stalk (Finley, 1934). The tubercles of the pellicle also 

 stain, as do the secretions of the pellicle, but the latter have been consid- 

 ered in the section on secretion granules and the former do not seem to 

 me to fulfill the definition of cytoplasmic granules, or at least are clearly 

 not in the same class as the ectosomes of Opalina. As a contrast to these 

 Protozoa with several types of segregation granules, the ciliate Ichthy- 



