604 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Kofoidi, Peridmiumformosum, P. Pauheni, Phalacroma hastatum, Dino- 

 physis Schroederi. In all, some eighty species have been collected in 

 the Etang de Thau and Gulf of Lyons, a rich flora as compared with 

 that of the English Channel. 



Bacillariacese from South Patagonia.*— 0. Miiller gives a list of 

 species collected by E. Nordenskiold and 0. Borge in 1899 in South 

 Patagonia, in ten different localities. Several new species and varieties 

 are described. 



Some New Chrysomonadineae. t — A. Pascher, during his recent 

 study of the micro-flora of Bohemia, paid special attention to the 

 Chrysomonadineae, and in the present paper he makes remarks on and 

 describes sis new species, belonging to four genera, Chromulina, 

 Chrysopyxis, Ocliromonas, and Derepyxis. He finds that very few of 

 the Chrysomonadineae are to be found in plankton, but that they prefer 

 to live in former beds of streams and other undisturbed places which 

 are becoming gradually filled up by their abundant marginal flora. 

 They also like very clear, cold, rather shady springs or pools at an altitude 

 of 500-1400 metres, which have never been disturbed for very many 

 years. The paper concludes with a key to the species of Derepyxis. 



Fertilisation in Zygnema.}— P. A. Dangeard bas studied the 

 chromatic reduction in Zygaema stellinum, and gives his results in a 

 short note. Both vegetative and reproductive filaments were examined. 

 The first point of interest is the absence of chromatic reduction before 

 fecundation. Vegetative mitoses, like those which directly precede the 

 formation of gametes, show the same number of chromosomes ; the 

 author has regularly counted a dozen, be it at the prophase, at the 

 stage of the equatorial plate, or at the anaphase. 



The next points to be elucidated are :— (1) the formation of the 

 egg, and (2) the aberrant forms of oospores. The distinction of the 

 male and female filaments takes place fairly early. In the males, the 

 axis, formed by the two chromatophores and the nucleus lies perpen- 

 dicularly to the filament, and it preserves this position while advancing 

 later into the canal. In the females, the chromatophores and the 

 nucleus retain tneir normal position along the axis. 



After the disappearance of the separating membrane of the copula- 

 tive canal, the male gamete advances towards the female gamete, while 

 preserving the same orientation ; it is then that fecundation takes place. 

 The anterior chromatophore moves away and the two nuclei, coming 

 into contact, fuse rapidly. The oospore rounds itself off and becomes 

 inclosed in a membrane which consists of cellulose endospore and a 

 cutinised exospore. Details are given by the author as to the nucleus 

 of conjugation and as to the behaviour of the nucleus in zygospores of 

 irregular formation. Finally, the author states that this species shows 

 all the stages between heterogamy, isogamy, and parthenogenesis, and 



* Engler's Bot. Jahrb. Beibl., xliii. (1909) pp. 1-40 (2 pis.), 

 t Ber. Deutsch. Bot. Gesell., xxvii. (1909) pp. 247-54. 

 t Comptes Rendus, cxlviii. (1909) pp. 1406-7. 



