Cytologie und Befruchtung. — Physiologie. 569 



chromic acid 25 cc. 1 per cent. acetic acid 10 cc, and water 

 65 cc). 



While all writers agree that the young oogonium of 

 Vaucheria is multinucleate and becomes uninucleate at matu- 

 rity, previous investigators have claimed that the uninucleate 

 condition resulted from successive nuclear fusions, or from the 

 return, of all the nuclei but one into the filament before 

 the oogonium is cut off by a wall. The points in Dr. Davis' 

 paper are as follows: The number of nuclei in the young 

 oogonium ranges from 20 to 50. There are no mitoses in the 

 oogonium. A cross wall developed between two plasma mem- 

 branes separates the young oogonium from the main filament. 

 Even before this wall is complete, a process of nuclear de- 

 generation is evident and it continues until only one nucleus 

 remains in the oogonium. The degenerating nuclei are found 

 chiefly in the periplasm. They become very small, the nuclear 

 membrane disappearing first and finally nothing remains but 

 granulär matter apparently nucleolar in nature. There is no 

 coenocentrum but the surviving nucleus lies at the center of 

 the oogonium in a dense mass of protoplasm which may re- 

 present a region of metabolic activity, so that the selected egg 

 nucleus probably owes its survival and growth to its favorable 

 Situation in the cell. The egg nucleus increases in size and 

 in chromatin content as does also the sperm nucleus. At the 

 time of fusion the sperm nuclei are of approximately the 

 same size. 



Oogenesis in Vaucheria agrees in important particulars 

 with oogenesis in Saprolegnia and the Peronosporales. In all 

 of these, the oogonium is separated from the filament as a 

 multinucleate cell in which the number of nuclei becomes 

 greatly reduced by nuclear degeneration, until, in some forms, 

 onlv one nucleus survives. The writer believes that Vaucheria 

 offers a serious objection to the view that mitoses in the 

 oogonia of Saprolegnia and the Peronosporales are reduction 

 divisions. All the nuclei in the oogonia of Vaucheria, Sapro- 

 legnia and the Peronosporales are regarded as homologous, 

 whether they are functional or merely potential. The author 

 suggests that the oogonia of these forms are related, at least 

 as gametangia, through remote ancestors, if not as fully diffe- 

 rentiated oogonia. 



The paper ends with a discussion of the evolutionary pro- 

 cesses effecting multinucleate organs in the Phycomycetes and 

 possible algal relatives. Charles J. Chamberlain (Chicago). 



BÜTSCHLI, 0., Notiz über die sogenannte Florldeen- 

 Stärke. (Verh. d. Naturhist. Medic. Vereins Heidelberg. N. F. 

 Bd. VII. Heft 4. 1904. p. 519—528.) 



Makro- und mikrochemische Untersuchungen an Florldeen- 



stärke führten zu dem Resultat, dass die Reactionen der letzteren 



