CI/ADOPHORA. 



247 



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chromatophores (Fig. 95, ch), separated by delicate colourless 

 lines. In each plate more or less numerous pale grains (a) can 

 be seen ; beside these lie comparatively 

 large, more or less regularly spherical 

 bodies, more strongly refractive, which 

 are known as pyrenoids (p), which have 

 a protein reaction. Each pyrenoid is 

 surrounded by a sheath of starch, The 

 cells are seen to be filled internally with 

 cell-sap, which is traversed by colourless, 

 exceedingly thin cytoplasmic plates, 

 which, proceeding from the lining layer, 

 divide the cell cavity into irregular, un- 

 equal, polygonal chambers. Here and 

 there chromatophores can be seen in the 

 inner protoplasmic plates. By focussing 

 so as to get an optical section, it will be 

 seen that colourless protoplasmic spheres 

 here and there project from the lining 

 layer into the general vacuole of the cell- 

 sap. These are the nuclei, and in 

 each, in especially favourable situations, 

 a nucleolus can also be distinguished. 

 In Gladophora, as is clearly proved by 

 this examination, we have therefore 

 multinuclear cells, or the whole thallus 

 may be said to be non-cellular, If now 

 the preparation is pretty strongly crushed, 

 we see in the flattened cells, the con- 

 tents of which are somewhat withdrawn 

 from the walls, the individual chlorophyll 

 plates, separated from one another, and 

 rounded. At the same time the small grains and pyrenoids show 

 up clearly in the chromatophores, which now 7 appear, like the 

 chlorophyll grains of higher plants, acted upon by the water. If 

 we now add a little iodine solution to the preparation, the small 

 grains, and also the outer sheath of the pyrenoids, colour violet, 

 and are thus proved to be starch ; in the green chromatophores, 

 however, they appear brown, and the nuclei, visible here and there, 

 also take a brown colour. We must not omit in this preparation 

 to search for uninjured cells, in which starch grains and amylum 



FIG. 95. Cladophora glo 

 merata. A cell of a thread 

 from a chromic-carmine pre- 

 paration, n, a nucleus ; ch, 

 chromatophores ; p, pyren- 

 oids ; a, starch grains ( x 540). 



