ZOOLOGY AND BOTANY, M1CKOSCOPY, ETC. (i79 



and on cabbage immersed in water. The eonids and oosperms invariably 

 produce germ-tubes. The mycele, eonids, oogones, and antherids are 

 multinucleate, the oosphere and the ripe oosperm uninucleate, and the 

 young oosperm binucleate. The nuclei multiply in the mycele and 

 sexual organs by indirect division. No nuclear fusions take place other 

 than those of the male and female nuclei in fertilisation. The number 

 of chromosomes is considerable, certainly 6 or more. The oogone re- 

 ceives 12 or more nuclei, the antherid 3 or more. These invariably 

 divide once, so that the number of nuclei is doubled. The supernumerary 

 nuclei in the oogone pass into the periplasm ; one only remains behind, 

 and occupies the centre of the ovum-cell. No similar differentiation 

 takes place in the antherid. The fertilisation-tube penetrates the wall 

 of the oogone, passes through the periplasm, and penetrates deeply into 

 the ovum-cell. One male nucleus passes down, and enters the ovum-cell. 

 The oosphere clothes itself with a delicate cell-wall, and proceeds to 

 digest and absorb the periplasm. The male and female nuclei do not 

 fuse until a thick oosperm-wall has been produced. As the oosperm 

 ripens, a reserve globule is formed in the centre of the oosperm, and the 

 fusion-nucleus is forced to one side. No epispore is developed. 



New Chytridiaceae.* — E. de Wildeman describes the following new 

 or little-known species of parasitic Chytridiacea) : — Olpidium Stigeoclonii 

 sp. n., within the cells of Stigeoclonium ; Bhizophidium Schrceteri sp. n., 

 in the plankton of the Lake of Zurich, especially on Aster ionella gracil- 

 lima ; B. Vauclierise sp. n., and B. multipornm sp. n., within the oogones 

 of Vauclieria sessilis ; Olpidium tumsefewievs sp. n., on the rhizoids of an 

 alga probably belonging to the Florideaa. 



Germination of the Spores of Penicillium. y — Further experiments 

 by P. Lesage on the germination of the spores of Penicillium glaucum in 

 moist air, bring him to the conclusion that it depends less on the absolute 

 quantity of aqueous vapour in the air than on its hygrometric condition. 



Aspergillus.^ — C. Wehmer discusses this genus of Fungi under the 

 following heads : — mycele, conidiophore, fructification, cultivation, influ- 

 ence of temperature, light, and oxygen, pigment, variability, sensitiveness 

 to toxic substances, classification. Herr Wehmer maintains his previous 

 arrangement of the species into 4 groups, distinguished by the colour of 

 the young conid-masses. viz. green, blackish, white, and brown-yellow. 

 The number of clearly distinct species described is 102. A copious 

 bibliography is appended. 



Biology of the Erysipheae.§— Dr. F. W. Neger finds, in other genera 

 of Erysipheae, contrivances similar to those which he has described in the 

 case of Phyllactinia, for anchoring the perithece to the substratum by 

 means of mucilaginous rows of cells or other modes of attachment. This 

 occurs in Sphserotheea and Er;/siphe. In most of the other genera, on 

 the contrary — Podosphsera, Microsphsera, Uncinula, &c. — the perithece 



* Mem. Herb. Boissier, 1900, No. 15. See Bot. Centralbl., Ixxxvii. (1901) p. ICO. 



t Comptes Eendus, exxxiii. (1901) pp. 174-6. Cf. this Journal, 1890, p. 338. 



t Mem. Soc. Buys, et Nat.-B.ist. Geneve, xxxiii. (1901) 153 pp. and 5 pis. Cf 

 this Journal, 1890, p. 235. 



§ Flora, lxxxviii. (1901) pp. 333-70 (3 pis.). Cf. this Journal, 1900. p. 494: ante 

 p. 72. 



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