CYTOPLASMIC INCLUSIONS 145 



Further work has extended the number of such cases in cihates and 

 flagellates, but at the same time it has been definitely proved that the 

 vacuoles in several species of both classes are never osmiophilic. An 

 examination of these cases shows that they form a closely graded series 

 ranging from no impregnation at any time to complete impregnation at 

 all times. Fabrea has no ectoplasmic Golgi bodies and no osmiophilic 

 contractile vacuoles (Ellis, 1937). Lechriopyla has many ectoplasmic 

 Golgi bodies, but they never form an aggregation around the contractile 

 vacuole (Lynch, 1930). Epid'mhm, Eudiplodinium (Fig. 54), and oth- 

 ers show an accumulation of granules only during diastole (Kra- 

 scheninnikow, 1929; MacLennan, 1933). This same type is found in 

 IchtJjyophthirms in the parasitic stages (Fig. 48), but neither free osmio- 

 philic ectoplasmic granules nor accumulations around the contractile 

 vacuoles during encystment (MacLennan, 1936) are present. Meta- 

 d'm'ium (Fig. 55) has a permanent granular nephridioplasm which 

 waxes and wanes during the pulsatory cycle (MacLennan, 1933). Va.ra- 

 mecium caudatum and P. nephridiatiim have a permanent osmiophilic 

 shell around the radiating canals, but not around the contractile vacuole 

 itself (Nassonov, 1924; von Gelei, 1928) . Haptophrya possesses a vacuo- 

 lar apparatus which consists of a permanent, homogeneous osmiophilic 

 tube (Bush, 1934). This nicely graded series shows that the impregna- 

 tion of parts of the vacuolar apparatus is due to aggregations of osmio- 

 philic granules around the fluid vacuoles and their membranes. The 

 only cases in which the membranes themselves impregnate are those ex- 

 tremely specialized cases in which the osmiophilic material forms a 

 permanent shell around the fluid vacuole. The highly complex osmio- 

 philic apparatus in either Paramecium or Haptophrya is fundamentally 

 no different from those vacuoles with a granular layer, and the homo- 

 geneous osmiophilic shells are merely the result of the aggregation and 

 specialization of the ordinary undifferentiated ectoplasmic Golgi bodies. 

 This view is similar to that of Nassonov (1924) and Hirschler (1927), 

 except that these authors view the osmiophilic portion as the outer por- 

 tion of the dictyosomes, and the fluid vacuole as the inner portion of the 

 dictyosome structure. Both views are, of course, the same, if the osmio- 

 phobic portion of the dictyosome be accepted as a secretion droplet and 

 not as an essential part of the dictyosome itself, as held by Gatenby and 

 Subramaniam and Ganapati. 



