164 Autonomy of Cell-Organs 



Hence it was clear that their limiting membrane must have 

 been derived from the granular plasm/^ 



In the formation of the endosperm a new plasmatic 

 membrane seems to be formed only in contact with that 

 of the mother-cell. In small embryo-sacs, where each 

 nuclear division is followed by a cell-division, the condi- 

 tions are, evidently, not essentially different from those in 

 vegetative cell-division. And, for those embryo-sacs 

 which continue to grow after fructification, I am not able 

 to find, in the literature in question, any proof against the 

 correctness of this assumption."^^ 



In a number of algae (e. g., Acetabularia, Hydrodict- 

 yon, Ulothrix) the swarm-spores arise from only a part 

 of the protoplasm of the mother-cell. In such a case this 

 part is always the peripheral layer, and every swarm- 

 spore receives, as far as the present literature allows us 

 to judge, not only a nucleus, chromatophores, and vac- 

 uoles," but also a part of the limiting membrane of the 

 mother-cell. Similar conditions seem to exist among the 

 fungi, e. g., in Protomyces macrosporusJ^ In the case 

 of Hydrodictyon, Pringsheim states that the colorless, 

 ciliated, anterior end of the swarm-spores represents the 

 maternal membrane.^^ In the Saprolegniacese also, the 



'^At this point in the original occurs a discussion of the pro- 

 cesses of cell-division within the embryo-sac in their relation to the 

 question of the autonomy of the limiting membrane. Since the 

 points there considered are now definitely settled and agreed upon, 

 the two paragraphs are here omitted with the author's approval. Tr. 



''^See especially Hegelmaier, Zur Entwickelungsgeschichte endo- 

 spermatischer Gewebekorper. Bot. Zeit. 44: 529, 545, 561, 585. 1886. 



^''According to the communication by Went mentioned on p. 154. 



^^Cf. de Bary. Vergleichende Morphologic und Biologie der 

 Pilze, Mycetozoen und Bacterien, p. 86. 1884. 



'^^Monatshericht Kais. Akad. Berlin, p. 246. 1871. 



