110 SUMMARY OP CURRENT RESEARCHES RELATING TO 



zoospores are rounded and collected into palmelloid groups. Thirty- 

 nine species of Nostochinese are described, and ten of ChroococcaceaB. 



Algse of the Indian Ocean.* — Herr P. Hauck describes Dictyota 

 atomaria obtained from Bombay at a depth of from two to four metres. 

 The frond is capable of forming, by proliferation, a new stalked 

 branch. The tetrasporangia and antheridia are found on different 

 individuals ; the latter form elongated or oval whitish spots, not 

 exceeding 1 mm. in breadth. 



Marchesettia spongioides, belonging to the Areschougiace^, has a 

 remarkable resemblance to a sponge ; it is found at Singapore, in 

 New Caledonia, and in Madagascar. The tetrasporangia and cysto- 

 carps develope at the summit of peripheral branches. The cystocarps 

 belong to one of the most complex types ; the sporiferous nucleus 

 has in its centre a large placental cell. 



Phseothamnion, a new Genus of Fresh-water Algse.f — Under 

 the name Phseothamnion confervicola, Herr Gr. Lagerheim describes a 

 freshwater alga forming brownish-yellow tufts on Vaucheria, Clado- 

 phora, &c. Each tuft consists of a relatively small filament with 

 monopodial branching, which takes place in the same way as in Clado- 

 phora. The cells are cylindrical or ovoid, with a parietal ribbon- 

 shaped brownish-green chromatophore. No nucleus, pyrenoids, or 

 starch, could be detected in them. The lower cells of the primary 

 axis and the basal cells of the older branches become sporangia, 

 swelling up, and forming two zoospores by bipartition, which then 

 escape through an opening in the cell-wall. The zoospores are 

 roundish, and have two equal cilia. They do not conjugate, but 

 attach themselves directly to an algal filament, and surround them- 

 selves with cell-walls. The germinating cell divides into two, the 

 upper one of which produces the filament by further growth and 

 division. A palmella-condition was also observed, in which the 

 cells divide in two directions, and become invested in a common 

 gelatinous envelope. 



Notwithstanding its brown pigment, Lagerheim refers Phseotham- 

 nion to the Chlorophycese, chiefly on account of the structure of 

 the zoospores, constituting a new family, Phajothamniese, near to 

 Chroolepideae and Chgetophoreee. 



Chlorochytrium Cohnii.l — Herr G. Lagerheim has had the 

 opportunity of further examining this parasitic alga, discovered by 

 Wright.§ It is interesting as being parasitic on animals, Campanu- 

 laria, Vaginicola, &c., as well as upon algte, — Schizonema, Vrospora, 

 Enter omorpha, &c. The separate cells vary in form : — spherical, 

 elliptical, flask-shaped, or quite irregular ; the chromatophore forms 



* Hauck, F , ' Cenni sopra alcune Alghe dell' oceano Indiano,' 4 pp. (3 pis.). 

 See Bull. Soc. Bot. France, xxxii. (1885). Kev. Bibl., p. 181. 



t Bih. K. Svenska Vet. Akad. Handl., ix. 14 pp. (1 pi.). See Bot. Ztg., xliii. 

 (1885) p. 604. 



t Ofvers. K. Vet. Akad. FSrhandl., 1884, 7 pp. (1 pi.). See Bot. Ztg., xliii. 

 (1885) p. 605. 



§ See tills Journal, i. (1S81) pp. 801, 931. 



