— 58 — 



type C there are no food particles in tlie body: thus out of 

 35 individuals singled out l3y me in a part of my prepara- 

 tions, only in 5 food was found. 



The nucleus is mostly of a regular spherical shape, but 

 sometimes becomes elongated into an ellipsoid. It possesses 

 a thick membrane, the contents of the nucleus being deta- 

 ched from the membrane. A similar detachment of the con- 

 tents of the nucleus from the membrane. A similar detachment of 

 the contends of the nucleus from the membrane is described and 

 figured in many Polymastigina and Hypermastigina. The 

 structure of the nucleus is mostly as follows: the nucleus 

 contains a large karyosome, the latter is in more simple cases 

 spherical (tab. 11, fig. 20), but more often elongated in one 

 direction, becoming oval or ovoid (tal). II, fig. 22). The kary- 

 osome may become still more elongated and reach the peri- 

 phery of the nucleus with one of its ends (tab. 11, fig. 25); 

 sometimes its second end may do the same, and then the 

 karyosome assumes the shape of a dark band cross-secting 

 the nucleus (tab. IV, fig. 44). In some cases the end of the 

 karyosome approaching the periphery of the nucleus becomes 

 expanded and the karyosome bears the likeness of a wide 

 wedge driven to the centre of the nucleus from its periphery 

 (tab. II, fig. 25). The spherical and oval karyosomes appear 

 to be homogeneous and are stained with Heidenhain's 

 haematoxylin into dark black. The karyosomes that are elon- 

 gated and expanded allow to establish the presence of two 

 different constituents in the karyosome, the chromatin and 

 the plastin. Very often the whole karyosome (when elongated) 

 consists of large, round grains of chromatin resembling the 

 chromosomes (tab. IV, fig. 44). In most individuals the karyo- 

 some is surrounded by a finely granulated grayish mass 

 (coagulated nuclear sap?). 1 did not succeed in finding a linin 

 network in the nuclei of type C. 



An undulating membrane is more or less adjacent to the 

 nucleus. The membrane is very small and tender. The whole stains 

 very weakly except a shnrp black line forming the base of the 

 membrane and a similar, but thinner line running' along the 

 margin of the membrane. In some especially successful pre- 

 parations I remarked that parallel to the margin-line, or fila- 

 ment, which stains intensely, there runs another finer fila- 

 ment. This filament, without any doubt, corresponds to the 



