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SUMMARY OF CURRENT RESEARCHES RELATING TO 
— have a very powerful effect in purifying water by the destruction of 
bacteria by the oxygen which they give out. Those algae which are 
enveloped in mucilage, especially diatoms, have a very prejudicial 
influence on drinking-water, by stopping the filters through which it 
passes. 
Vickersia, a new Genus of Floridese.* * * § — Among a collection of sea- 
weeds from the Canary Islands, Mdlle. N. Karsakoff finds one which she 
regards as a new type of Ceramiaceae, with the following diagnosis : — • 
VicJcersia. Frons tota articulata, monosiphonia, ecorticata, repens, 
radiculis apice scutellatim expansis affixa ; fila primaria cylindrica, 
inferne irregulariter ramosa ; ramis erectis, ad genicula opposite aut 
verticillatim ramulosis ; ramuli vegetativi simplices, saepius ex articulo 
unico crassius-inflato, nunc ad basim ramorum articulis pluribus cylin- 
dricis constantes ; ramuli tetrasporiferi biarticulati, articulo inferioro 
tetrasporas numerosas circumcirca praegnante ; tetrasporse sphmricac, 
triangule divisas, sessiles. Cystocarpia et antheridia desiderantur. 
Until the cystocarps have been found, the genus is placed provisionally 
near to Griffithsia. 
Hew Freshwater Floridea.f — Under the name Delesseria zanzi- 
bariensis, Prof. K. Goebel describes what he regards as an addition to 
the very small number of freshwater Florideae at present known, from 
Zanzibar. 
Miss E. S. Barton J regards the alga as probably identical with 
Caloglossa Leprieurii. 
Reproduction of Coleochsete.— -Herr F. Oltmanns § confirms, in the 
main, in the case of Coleoclisete pulvinata, the correctness of Pringsheim’s 
description of the mode of sexual reproduction in this genus ; but he 
does not assign to it so high a position among Algae as has generally 
been done. It is probably most nearly allied to the (Edogoniaceae ; the 
resemblance to the Florideae is more apparent than real. The zoo- 
sporanges, antherids, and oogones are perfectly homologous organs ; the 
oogones are but a slight modification of the zoosporanges. During 
winter the resting oosperm remains without change ; it always contains 
a parietal nucleus, a large central vacuole, and eight chloroplasts, each 
with its own pyrenoid. On germinating the oosperm divides, by a 
vertical wall, into two cells, each with a nucleus and four chlorophyll- 
bodies ; after two further divisions, each of the eight cells has a single 
chlorophyll-disc. 
Observations made by Prof. R. Chodat || on the mode of reproduction 
of Coleochsete confirm his previous view that there is in this genus of 
Algae no true alternation of generations. The fertilised oosphere does 
not give birth directly to the thallus, but to two groups of cells more or 
less adherent, which finally become liberated like many spores. These 
latter germinate directly into a small rudimentary thallus. The so- 
called sporogone is formed by the concrescence of the products of the 
division of the ovum within the cortical tissue. 
* Ann. Sci. Nat. (Bot.), iv. (1897) pp. 281-91 (1 pi.). 
t Flora, lxxxv. (1898) pp. 65-8 (6 figs.). 
X Journ. of Bot., xxxvi. (1898) pp. 195-7. 
§ Flora, lxxxv. (1888) pp. 1-14 (2 pis.). 
|| Arch. Sci. Phys. et Nat., v. (1898) pp. 100-1. 
