278 SUMMARY OF CURRENT RESEARCHES RELATING TO 



case of S. tenue, withoiit any such division. In Draparnaldia ghmerata 

 f3 hiformis, and in Chsetophora tuberculosa, the cysts are formed either in 

 the ordinary way within the cell, or the contents escape and clothe them- 

 selves with a new cell-wall outside the mother-cell ; in the former species 

 the cysts produced in this way form mouiliform rows of cells attached to 

 the thallus. 



The cysts may either remain green during their period of dormancy, or 

 may become deeply coloured by an orange j)igment ; the former is the case 

 especially where desiccation has not been complete. 



Tannin in Algae.* — M. E. De Wildeman has investigated the occurrence 

 of tannin in fresh-water algfe. All the algas examined, except the Nosto- 

 cacese and Batrachospermese, whether iioating on the surface of the water 

 or fixed to the bottom or terrestrial, whether affecting marshes or calcareous 

 waters, were found to contain larger or smaller quantities. M. Wildeman 

 repards the taunin as not a mere product of excretion, but as performing an 

 active function in assisting assimilation. The best test for its presence, at 

 least in algae, is the reaction with salts of iron. 



Morphology of Polysiphonia.f — M. K. Eosenvinge describes the mode 

 of formation of the tetraspores, antheridia, and cystocarps, in several species 

 of Polijsiphonia. The two latter organs he regards as leaves or modified 

 parts of leaves. The mode of branching and leaf-divergence are also 

 described. In P. fastigiata peculiar annular formations occupy the inter- 

 cellular spaces between the central cell and the pericentral cell. 



Epiclemmydia lusitanica, a new species of Alga. J — Mr. M. C. Potter 

 has investigated the life-history of a new species of alga, now named 

 Epiclemmydia lusitanica, which lives on the backs of the tortoises inhabiting 

 the pools of Southern Europe. This alga, which to the naked eye appears 

 as small green roundish patches, is found to consist of a number of cells 

 closely applied to the tortoise-shell, but which are only a few layers deep, here 

 and there penetrating into the shell and causing it to flake off. The cells 

 next to the shell always force their way into any available crack, where 

 they divide, and thus penetrate to some depth. The alga is reproduced 

 by means of zoospores formed in the external layer of cells. These 

 zoospores are all exactly similar, and swim about for a considerable time, 

 after which they come to rest, and germinate. 



Arctic Algse.§ — Prof. W. G. Farlow publishes a descriptive list of 

 Arctic algfe, collected chiefly in Ungava Bay. It is distinguished by the 

 large number of Floridese, rare in Arctic latitudes. Among the material 

 collected by L. Kumlien he describes twenty-two species of Floridese, 

 thirteen of Phaeosporefe, and five of Chlorosporcfe. 



Phycotheca Italiana. — The first fascicle of this publication by Signori 

 G. B. Toni and D. Levi has appeared, comprising fifty species of algae, 

 marine and fresh-water, all from the Venetian territory. 



Scandinavian Alg8e.|| — M. G. Lagerheim describes seventy interesting 

 species or varieties of algae gathered in Sweden, including eighteen new 

 species, chiefly desmicls and Cyanophyceae. Among the species described 

 and figured is a new Oocystis, 0. suhmarina. 



* CR. Soe. R. Bot. Belg., ISSG, pp. 132-43. Cf. tins Journal, 1884, p. 832. 

 t Bot. Tids.-kr.,xiv. See Bull. Soc. Bet. France, viii. (188(J), Rev. lUl 1., p. 149. 

 i Proc. Cambridge Pliil. Soc, Nov. 8, 188G. See Nature, xxxv. (1887) p. 214. 

 § Proc. Amer. Acad. Art.s and Sci., 1886, pp. 469-77. 



II Bot. Notiser, 188G, pp. 44-50. See Bull. Soc. Bot. Fiance, viii. (1886), Rev. Bibl., 

 p. 158. 



