626 SUMMARY OF CURRENT RESEARCHES RELATING TO 



detect the two nuclei in the zygote after conjugation, which afterwards 

 coalesce. The formation of the membrane of the spore probably takes 

 place by apposition. 



Uronema, a new genus of Chlorozoosporeae.* — Herr G. Lagerheim 

 gives the following diagnosis of this new genus of Algfc, which ho 

 regards as a connecting link between the Chajtophoraccaj and tho 

 Ulothricacea) : — Fila non ramosa, muco non involuta, c serie siniplici 

 cellularum formata, basi adnata. Cellula apicalis attenuata. Membrana 

 ccllularis tenuis et hyalina, non lamellata. Nuclei cellularum siuguli. 

 Chromatophori singuli, parietalcs, lamiuiformcs, viridos, margino 

 infequali, pyrenoidis binis (rarius singulis) praiditi. Megazoosporaj 

 singula), rarius bina) (vel complures ?) e contcntu cellularum omnium 

 fili non mutatarum orta), ovoidea), ciliis vibratoriis quatcrnis et puncto 

 rubro prsedita), per ostiolum magnum poriforme vel cellula parte mediana 

 membranfe gelificata fracta examinantcs, germinantes fila nova formantes. 

 Aplanosporai contractione contentus cellulfc formats) (vel e zoosj)ori8 

 orta) ?). 



The species on which the genus is founded, U. confervicohim, was 

 found by the author epiphytic on filaments of Conferva in ditches near 

 Warberg in Sweden. He thinks it probable that Stigeoclonium sim- 

 jjlkissmiim Eeinsch belongs to the same genus. 



Wille's Contributions to Algology.t — Prof. N. Wille publishes in 

 German a number of his observations on various classes of Algfe, most 

 of which have appeared before only in Swedish. They comprise : — On 

 the swarm-cells of Trentejwhlia and their conjugation ; J On a new endo- 

 phytic alga (Eniodadia Wittrockii) ; § On cell-division in Conferva ; || 

 On cell-division in (Edogonium ; \\ On the germination of the swarm- 

 spores of (Edogonium ; % On the resting-cells of Conferva;** On the 

 genus Gongrosira ; ^\ and on akinetes and aplanospores ; JJ as well 

 as the paper on Chrysopyxis hipes and Dinohryon sertularia.%% In the 

 paper on Gongrosira, Prof. Wille gives this definition of his terms 

 alcinetes and aplanospores : — The former are non-motile reproductive 

 cells produced non-sexually and without rejuvenescence ; the latter are 

 non-motile reproductive cells produced non-sexually by rejuvenescence. 

 Akinetes occur in Trentepohlia, Conferva pachyderma, and Ulotlirix, as 

 well as in the so-called sj)ores of Nostocacere and Eivulariaceae ; aplano- 

 spores in Conferva stagnonim and WittrocJcii. The two kinds of resting- 

 cells pass into one another, and akinetes into ordinary vegetative cells, by 

 insensible gradations. 



Hansgirg's Alga-flora of Bohemia. HH — Prof. A. Hansgirg has now 

 completed the first part of his important ' Prodromus of tlie Alga-flora 

 of Bohemia,' comprising the Ehodophycefe, Phaeophyccfe, and Chloro- 

 phyceae. The number of species described is 523, each genus being 

 illustrated by one or more woodcuts. 



Hansgirg agrees with Eostafinski in including Hydriirus and Chromo- 



* Malpighia, 1. (1887) pp. 517-23 (1 pi.). 



t Pringsheim's Jahrb. f. Wiss. Bot., xviii. (1887) pp. 425-518 (4 pis.). 



X See this Journal, 187D, p. 601. § Ibid., 1880, p. 1023. 



II Ibid., p. 1024. TI Ibid., p. 1025. ** Ibid., 1882, p. S3G. 



tt Ibid., 1884, p. 107. JJ Ibid., p. 272. §§ Ibid., 1883, p. 863. 



nil Hansgirg, A., 'Prodr. d. Algenflora v. Bohmen,' Theil 1, Heft 2, Prag, 1888. 

 See Bot. Centralbl., xxxiv. (1888) p. 97. Cf. this Journal, 1887, p. 125. 



