INVERTEBEATA, CRYPTOGAMIA, MICROSCOPY, ETC. 493 



acid. The author regards this as confirmatory of his view as to tho 

 species. 



Algee. 



Cell-division in Algae.* — In a species of Conferva brought from 

 the interior of Greenland, M. KoLlcrup Roscnvinge observed a jieculiar 

 process pi'cceding cell-division, viz. tho formation and separation of 

 a very thin interior layer of cellulose ; a thickening tlien makes its 

 appearance in the middle of this interior layer, which grows and divides 

 the cell into two. A similar process was observed in a Ulothrix from 

 the marsh of Lyngby, which lie jiroposes to name U. leverrima var. 

 mucosa. 



Reproduction of Bryopsis.f — M. Max Coruu has recently been 

 studying the development of Bnjupsis at the Wimereux Zoological 

 Station. It was tolerably common at tho end of September and in 

 October. At tho end of tho third week in October the observations 

 were suddenly broken off. They were made on Bryojtsis plumosa, or a 

 robust form of JJrijopsis hypnoides. The following are his princi^Jal 

 conclusions : — 



The orange-coloured Bryopsis arc not specimens attacked by para- 

 sites ; the develi)pment ai)peiired normal mid regular ; the transforma- 

 tion of the protoplasm and the escape and disposition of the mobile 

 bodies which it ])roducos show this. 



The orange-coloured mobile bodies, whose length is less by one- 

 lialf that of the others, do not germinate ; but a similar capability of 

 alteration shows itself in the green zoospores, a peculiarity rare 

 amongst marine Alga3. 



The rare germinations which are effected take place by the forma- 

 tion of spherules of two forms, the development taking a month and a 

 half. 



It was natural to consider these two kinds of mobile bodies as tho 

 analogues of the sexual cor2)uscles of Pandorina, the red ones being 

 the spermatozoids. M. Cornu brought together under the Microscope 

 small droi)s of water charged with either kind, and saw no conjunc- 

 tion even whilst waiting fur the (quiescence of the green zoospores. 



M. Cornu noticed some green zoospores with four cilia; hut they 

 were rare. It seemed to him that, a priori, they ought to bo double, 

 and analogous to those of Botrydium. 



There are no female organs in the form of oogonia. Any near 

 comimriKon with Vanchcriti was impossible. Botrydium is probably 

 much nearer to BrycpiniH than to Spliu'voplca. 



In the vegetative or reproductive filaments some short cells lie iso- 

 lated liere and there, whose function is ])r()bably that of asexual spores. 



Plurality of Nuclei in the Cells of the Siphonocladiaceae.J — 

 Tlie group Siphonoeladiaceie has been defined by Sehmitz § as in- 

 cluding tho marine algus Valonid, Siphouurladu8,Anadyumcne, Micro- 



* *Bot. TillHskr.,' iii. (187'.t) p. 2 (Sui)|iliiiifnt, Freuch re'sumd). 

 t • C<)iiii>t<« liLiuluM,* Ixxxi.x. (I«7'.)) |>. J(I4!>. 

 X 'SH. Nifdurrii.iii. <ins. Natur- ii. Hcilk.,' Bonn, May 5, 1879. 

 § Sec thid Juuruul, ii. (lb7D) |>. OUU. 



