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EISEN. 



[VOL. I. 



some. This division is in accordance with the one proposed in 

 my paper on the plasmocytes in the blood of BatracJioseps}- 



The cytosome comprises all that part of the cell situated 

 exterior to the nucleus except the archosome. The cytosome 

 contains the following distinct structures : cytoplasm proper, 

 plasmosphere, hyalosphere, granosphere, metaplasmic secre- 

 tions, cytoplasmic membrane, and cell wall. None of these 



FIG. i. A polymorphous spermatogonium in the " perfect resting stage." The form of the nucleus 

 allows the most perfect metabolism. Numerous chromioles are connected by a thread of 

 chromoplasma. A network of linosomes is partially indicated, the individual granules being 

 connected by Linopodia. A large chromoplast with endochromatic granules. Eight par.i- 

 (hromatic grannies. A single archosome in the cytoplasm, the latter only partially indicated 

 by small open circles. A single large linoplast, with seven endonucleolar granules. 



structures arc in any way intimately connected with the archo- 

 some. The three spheres mentioned above surround each other, 

 like three concentric shells, at the time when the cell is in par- 

 tial resting stage ; but at a later stage, or as soon as the prophase 

 is entered, these spheres break up and scatter in the cytoplasm 

 proper. Each one of the spheres constitutes an independent 

 structure, and they are not developed one from the other. 



1 7W. Cal. Acad. Sfi., 30! Ser., Zool. Vol. i, No. i. 



