82 PROTOZOOLOGY 



chondriosomes are reformed de novo. On the other hand, Faure- 

 Fremiet, the first student of the chondriosomes in Protozoa, main- 

 tained that they reproduce by division, which has since been con- 

 firmed by many observers. As a matter of fact, Horning found in 

 Opalina, the chondriosomes are twisted filamentous structures and 

 undergo multiple longitudinal fission in asexual division phase. Be- 

 fore encystment, the chondriosomes divide repeatedly transversel}' 

 and become spherical bodies which persist during encystment and 

 in the gametes. In zygotes, these spherical bodies fuse to produce 

 longer forms which break up into elongate filamentous structures. 

 Richardson and Horning further succeeded in bringing about divi- 

 sion of the chondriosomes in Opalina by changing pH of the medium. 



As to the function of chondriosomes, opinions vary. A number of 

 observers hold that they are concerned with the digestive process. 

 After studying the relationship between the chondriosomes and 

 food vacuoles of Amoeba and Paramecium, Horning suggested that 

 the chondriosomes are the seat of enzyme activity and it is even 

 probable that they actually give up their own substance for this 

 purpose. Mast (1926) described "beta granules" in Amoeba proteus 

 which are more abundantly found around the contractile vacuole. 

 Mast and Doyle (1935, 1935a) noted that these spherical to rod-like 

 beta granules are plastic and stain like chondriosomes and that there 

 is a direct relation between the number of beta granules in the cyto- 

 plasm and the frequency of contraction of the contractile vacuole. 

 They maintained that these granules "probably function in trans- 

 ferring substances from place to place in the cytoplasm." Similar 

 granules are recognizable in the species of Pelomyxa (Andresen, 

 1942; Wilber, 1942; Kudo, 1951). 



The view that the chondriosomes may have something to do with 

 the cell-respiration expressed by Kingsbury was further elaborated 

 by Joyet-Lavergne through his studies on certain Sporozoa. That 

 the chondriosomes are actively concerned with the development of 

 the gametes of the Metazoa is well known. Zweibaum's observation, 

 showing an increase in the amount of fatty acid in Paramecium just 

 prior to conjugation, appears to suggest this function. On the other 

 hand, Calkins found that in Uroleptus, the chondriosomes became 

 abundant in exconjugants, due to transformation of the macronu- 

 clear material into the chondriosomes. The author agrees with 

 McBride and Hewer who wrote: "it is a remarkable thing that so 

 little is known positively about one of the 'best known' protoplasmic 

 inclusions" (Piney, 1931). Condriosomes in Protozoa (MacLennan, 

 1941; Grasse, 1952). 



