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PROTOZOOLOGY 



In many other Protozoa, the division figure, especially the 

 achromatic figure, suggests strongly a mitosis, but the chromatin 

 substance which makes up the equatorial plate can hardly be 

 called chromosomes. A typical example of this type is found in 

 the nuclear division of Amoeba proteus (Fig, 62). According to 

 Chalkley and Daniel (1933), the conspicuous granules present in 

 the resting nucleus, under the membrane contain very little 

 chromatin, while abundant chromatin is lodged in the central 



Fig. 62. Nuclear division in Amoeba proteus, X180 (Chalkley and 

 Daniel), a, resting stage; b-d, prophase; e, metaphase; f, g, anaphase; 

 h, a daughter nucleus. 



area. The peripheral granules appear to give rise to achromatic 

 figure. At the beginning of division, the chromatin granules 

 become aggregated in a zone (6); they then assume a ring-form 

 along the periphery of the central mass of network (c); at this 

 stage, the cytoplasm around the nucleus is much vacuolated. A 

 little later appears a discoid equatorial plate or ring which is 

 connected with the nuclear membrane by numerous fibrils, and 

 the nucleus becomes markedly flattened with its membrane still 

 intact (d), which is considered as the end of the prophase. In the 

 metaphase, the nuclear membrane becomes extremely faint and 

 the portion over one side of the plate is without it (e). At the 



