ZOOLOGY AND BOTANY, MICROSCOPY, ETC. L93 



o o 



Chemotaxis of Spermatozoids in Marchantia.* — A. Akerman gives 

 an account of his investigations into the chemotaxis of the spermatozoids 

 of Marchantia. The spermatozoids are attracted not only by proteid 

 matters but also by salts of potassium, rubidium, and caesium. The 

 spermatozoids become conscious of potassium salts and of proteid matters 

 by different and independent acts of perception. Sodium and calcium 

 salts have no such chemotactic action ; on the other hand the salts of 

 magnesium and ammonium exert a weak repulsion, and the salts of the 

 heavy metals a strong one. As to the spermatozoids, all their move- 

 meuts of this character are of a chemotactic nature ; they have no osmo- 

 tactic excitability ; but, as Lidforss has shown, they manifest a clear 

 aerotaxis. 



Mechanism of Cohesion in Moss-leaves.f — W. Lorch continues his 

 dispute with Steinbrinck about the mechanism of cohesion of PoJy- 

 trichum leaves. He is convinced that his opponent is wrong, and 

 adduces fresh arguments to prove it by the peculiar behaviour of cer- 

 tain cells under polarised light. 



Nomenclature of Sphagnum.} — A. Le Eoy Andrews criticises the 

 proposals, which Roll will lay before the coming International Con- 

 gress of Botanists at Brussels, concerning the nomenclature to be applied 

 to Sphagnum. These proposals are broadly as follows. 1. Sphagnum- 

 species are in their nature series of forms, and hence a type-form is an 

 impossibility. Species based on a single form or specimen are of little 

 value, and should give way to species described from a series of forms. 

 2. The description of a species (series of forms) should be short and 

 characteristic, and should not repeat the characters of the genus, varie- 

 ties, or forms. 3. Extension or completion of a description already 

 existent does not justify change of specific name or change of author's 

 nauie. 4. When within a genus a group is changed in rank or moved 

 into another group without change of rank, the first author shall be 

 cited, and the author for the change, if cited at all, be put in a paren- 

 thesis. Andrews regards Roll's proposals as founded on a fallacious idea 

 of the species and types, as an offence against the principles of binomial 

 nomenclature, as encouraging insufficient descriptions, and as generally 

 reactionary. 



British Bryophyta.§ — -0. B. Cramptou records the occurrence of 

 fruiting cushions of Dicranum Bergeri in Caithness, June 1908. 



J. A. Wheldon || records the finding of the very rarely fruiting Ulota 

 phyllantha with abundant capsules, near Kingsbridge, in S. Devon, by 

 H. Beesley in May 1909. 



E. Armitage IT gives a list of nine mosses and four hepatics, new- 

 records for the vice-counties Elgin and Easterness, among them being 

 I r lota phyllantha with fruit. A new record for Ayr is added. 



C. H. Waddell** publishes a supplementary note on the late J. H. 

 Davies and his connection with Thirsk and the mosses of Yorkshire. 



* Zeitschr. f. Bot., ii. (1910) pp. 94-103. 



t Ber. Deutsch. Bot. Gesell. xxvii. (1909) pp. 460-5. 



; Bryologist, xiii. (1910) pp. 4-6. § Journ. of Bot., xlviii. (1910) p. 23. 



|| Tom. cit., p. 57. f Loc. cit. ** Loc. cit. 



