ceratomyxa acadiensis. 559 



2. Sporogony. 

 A. Formation of the Sporoblasts. 



The first indication of the sporoblasts occurs when twelve of the 

 nuclei of the myxosporidium with the more deeply staining protoplasm 

 around them arrange themsehes in groups of sLx (PI. I, Fig. 17). 

 The formation of the sporoblasts by the coming together of cells 

 originally separate agrees with the observations of Awerinzew ( : 09) 

 on the formation of the spores in C'eratom^xa drepanopsettae Awer. 

 The young sporoblasts (PI. I, Figs. 17, 20, 25) lie side by side in the 

 myxosporidium. They are ellipsoidal and the sides in contact are 

 usually somewhat flattened (PI. I, Figs. 18, 20). The protoplasm of 

 the sporoblast is usually" clearly to be distinguished from that of the 

 myxosporidium by reason of its different reaction to stains, as seen 

 for example in Plate I, Figure 17, where the protoplasm of the sporo- 

 blast is deep blue, while the surrounding protoplasm is faintly stained. 

 A sharp differentiation of the protoplasmic masses surrounding the 

 separate nuclei of the sporoblast is not to be seen in Figure 17. Such 

 a differentiation exists, however, in later stages (PI. I, Figs. 18, 20, 

 23, 24), where capsulogenous cells ^ and valve-cells^ are clearly to be 

 distinguished from each other. 



It has not been possible to distinguish any difference in the nuclei 

 which are brought together in the formation of the sporoblasts. The}' 

 are uniform in size and stainability and show from four to ten deeply 

 staining granules, mostly at the periphery, connected by achromatic 

 strands passing through the nuclei. With Giemsa's stain these gran- 

 ules are deep purple or mauve and the achromatic strands are faint 

 red (PL I, Fig. 17). In certain cases when these nuclei are stained 

 with Delafield's haematoxylin a slightly larger granule is separated 

 from the rest. This granule probably represents the Binnenkorper 

 of Schroder (:07). The nuclei resemble those of the sporoblasts of 

 Sphaeromyxa sabrazesi Laveran et Mesnil as described by Schroder 

 (: 07), in their uniform size and chromatic structure, but differ in con- 

 taining a relativelv smaller number of chromatin granules. 



5 The term "capsulogenous cell" is used for the French "cellule capsulogene" 

 (Thelohan, '95, p. 280) and for the German "Polkapselzelle." 



6 The term "valve cell" is used for the French term " cellule d'enveloppe " 

 (CauUerv et Mesnil, :05) and the German term "Schallenzelle" (Keysselitz, 

 :08). 



