ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 565 



other Phycomycetes, with which he compares them. It is prohable that 

 conjugation takes place between the nuclei which remain behind in the 

 centre of the zygote. 



Biology of Leptomitus lacteus.* — E. Kolkwitz has succeeded in 

 growing in the laboratory this fungus which has its home in impure 

 water. Very little, however, is recorded of its mode of life, except that 

 its growth resembles that of Saprolegnia, to which it is nearly allied. 

 It would appear to be certainly nut an obligatory parasite. 



Rhizophagus populinus-f — Further study by P. A. Dangeard of 

 this parasite of the roots of the poplar has continued his opinion that 

 it belongs to the Chytridiniese. Its effects are exceedingly destructive ; 

 not only does it use up the nutritive substances carried to the cortex by 

 the root-hairs ; it completely digests also the contents of the cortical 

 cells, and prevents the roots from fulfilling their function. The forma- 

 tion of spherical cysts was observed, but not that of zoospores. 



Chytridium transversum4 — P. A. Dangeard describes the various 

 stages of development on this parasite of Chlamydomonas pulvisculus 

 and Gonium perforate. He has observed both zoospores and cysts, the 

 latter being unquestionably of a non-sexual character. 



Biology of Bulgaria.§ — R. H. Biffen has studied the life-history 

 and the effects on dead oak-wood of the saprophytic fuugus Bulgaria 

 polymorpha, which is a facultative parasite. The most noteworthy point 

 in the structure of the fungus is the dimorphism of the ascospores ; four 

 in each ascus having thick dark brown walls, and four being colourless 

 and thiu-walled. The two kinds of spore apparently behave alike on 

 germination. The result of the action of the fungus on oak-wood is to 

 dissolve and probably decompose the lignin and to dissolve the pectates 

 of the middle lamella. 



New Genus and Species of Laboulbeniaceae.|| — In addition to his 

 previous numerous discoveries, R. Thaxter now describes a number of 

 new species of this order, parasitic on the bodies of insects, belonging 

 to the genera Stigmatomyces, Arthrorhynchus, JRhizomyces, and Dimero- 

 myces ; also the following new genus : — 



Ceraiomyces g. n. Structure of perithecium as in Laboulbenia ; its 

 stalk-cell united to the free base of the free stalk-cell of the appendage, 

 which bears a well-differentiated basal cell terminally. On the end of 

 this are borne antheridial branches, the successive cells of which pro- 

 duce terminally either successive secondary branchlets, or antherids, or 

 both ; receptacle 2-celled. 



Conjugating Yeast, Zygosaccharomyces g. n. If — B. T. P. Barker 

 isolated from commercial ginger a yeast which was cultivated on 

 beer-wort gelatin, beer-wort agar, potato, bread, ginger, and in beer- 

 wort. A yeast-ring is formed in old cultures in many liquid media, 

 but no film was produced. The vegetation of the cultures consists of 



* Ber. Deutsch. Bot. Ges., xix. (1901) pp. 288-91. 



+ Le Botaniste (Dangeard), vii. (1901) pp. 285-7 (2 pis.). Cf. this Journal, 

 1897, p. 60. X T om. cit., pp. 282-4 (1 fig.). 



§ Ann. of But., xv. (1901) pp 119-34 (1 p].). 



|| Proc. Amer. Acad. Sri., xxxvi. (1901) pp. 397-414. Cf. this Journal, 1900, 

 p. 617. H Proc. Hoy. Soc, lxviii. (1901) pp. 345-8. 



Oct. 16th, 1901 2 q 



