ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 511 



Zygotes arise by the fusion of vegetative cells which are equivalent 

 to uninucleate gametes A copulating tube arises from the smaller male 

 cell and comes into contact with the larger female cell ; the apex of the 

 tube then swells up and receives the contents of both male and female 

 cells. Fusion takes place later between the nuclei with the extrusion of 

 masses of chromidia which fuse and form a granular mass, the " chrom- 

 idiosphere " or " chromidiocentrura." Germination of the zygote takes 

 place live months after fertilization by the formation of the small zoo- 

 sporangium, and only in the sporangia does nuclear fusion take place. 

 The process of division has been follow^ed : it is a perfectly normal 

 mitosis. 



Polyphagus shows relationship with Chytridiacese leading on the one 

 one hand to the Oomycetes, on the other to the Mucorace^. In its 

 general structure and in the formation of chromidia it also shows con- 

 nexion with the Protozoa. 



Wager sees in this fungus a double fusion, first of chromidia in the 

 zygote, and secondly of nuclear fusion in the sporangium ; and he con- 

 siders that the succession of events may afford some clue to the delayed 

 nuclear fusion and double nuclear fusions observed in the hii^her funsri. 



New Yeast.* — G. Lindau reports a fungus much used in Kurland 

 as a cure for nearly every kind of ailment. It is of a yeast nature, and 

 is cultivated by the country people on an infusion of sweetened tea. 

 If a small fraction of the skin formed in culture by the yeast is placed 

 in the tea solution it sinks at first to the bottom, then gradually slimy 

 offshoots are observed to spread upwards till they reach the surface, 

 where the characteristic " skin " is again formed. In the early stages 

 the fungus has a spicy fruity aroma, but in older cultures it acquires a 

 more vinegary odour. 



The yeast is composed of somewhat elongate cells, but as the " skin " 

 is the most striking formation, Lindau has named it Medusomyces Gisevii 

 g. et sp. n. The " skin " is much thicker than in Mycoderma. 



Uredinese.f — J. Ramsbottom has published an historical account of 

 the Uredineai from the earliest times up to the present. He traces the 

 different theories as to the origin and significance of rusts, and the 

 changing views concerning them as the years have passed and knowledge 

 has grown. Ramsbottom has also given a history of the classification 

 of the group. He has adopted Dietel's arrangement as given in Engler's 

 Pflanzenfamilien, the one now usually followed, and he adds a list of 

 all the recorded British species, with the spore-forms indicated and the 

 corrected nomenclature, so far as known. 



Ed. Fischer % has published a collective account of work on the 

 biology of the Uredineee published in 1912. Papers on cytology, on 

 wintering of the spores or of the mycelium, and on the conditions of 

 germination are fully discussed. The experiments to prove, by cultures, 

 related hetercecious rusts, are also recounted. Other work has been 



* Ber. Deutsch. Bot. Gesell., xxxi. (1913) pp. 243-8 (1 pi.). 

 t Trans. Brit. Mycol. Soc, iv. (1913) pp. 66-105. 

 X Zeitschr. Bot., v. (1913) pp. 470-1. 



