ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
335 
new species : — Reinschiella (?) setigera (Pleurococcaceae), with the ex- 
ternal habit of a Rhizosolenia ; Golenkinia fenestrata, sometimes in 
enormous quantities, each colony occasionally consisting of as many as 
64 cells ; and Telrapedia emarginata. 
Reproduction of Diatoms.* — Comte Abbe F. Castracane reviews the 
recent literature on this subject, confirming his previous view that the 
normal mode of reproduction of diatoms is by spores or by germs, and 
that multiplication by division, although very common, is the exception 
rather than the rule. The evidence of fossil diatoms shows that the 
siliceous wall is present from the first moment of the existence of the 
diatom, and that, like other organisms, it is small when first formed, 
gradually growing to its full size. 
Rhizosolenia and Attheya.j — In the plankton of the Plbner See, 
Dr. 0. Zacharias finds representatives of both these genera of diatoms, 
and argues for their very close affinity, if not identity. In Rhizosolenia 
he records, moreover, the formation of chains. 
Cause of Odours and Tastes in Drinking Waters. J — Mr. D. D. 
Jackson and Mr. J. W. Ellms point out that while some of the Cyano- 
phycese (especially Anabsena ) produce disagreeable odours in surface 
waters by the decay of nitrogenous organic matters, the usual cause of 
unpleasant odours and tastes occurring in potable water is the large 
numbers of certain microscopical organisms which secrete compounds 
of the nature of essential oils as a phenomenon of growth. Besides 
Anabsena, an odour of decay is produced by other Cyanophycese, — 
Rivularia , Clathrocystis, Goelospliserium, Aphanizomenon. The organisms 
■enumerated which emit odours of growth are the following : — Diatomacem 
( Asterionella , Tabellaria, Meridion) ; Chlorophyceae (Volvox, Pandorina, 
Eudorina) ; Infusoria ( Uroglena , Dinobryon, Synura, Bursaria , Peri- 
dinium , Cryptomoncis, Mallomonas). Most of these produce fishy, some 
of them aromatic smells. The odour of the Cyanophycese is produced 
by the decay of highly nitrogenous organic matter, in which partially 
decomposed sulphur and phosphorus compounds play the leading part. 
Gas-Vacuoles of Gloiotrichia.§ — In opposition to the view of Richter, 
Herr H. Klebahn maintains that the red bodies in Gloiotrlchia echinulata 
are gas-vacuoles, though the composition of the contained gas could not 
be ascertained. 
B. Sch.izomycetes. 
Myxobacteriaee8e.|| — Herr H. Zukal has now adopted Thaxter’s 
view § that this group of organisms must be ranked under the Schizo- 
mycetes rather than under the Myxomycetes. The structure which he 
before described as a plasmode is rather a pseudo-plasmode, i.e. it does 
not result from the coalescence of active swarm-cells, but is rather a 
collection of swarm-cells in which each retains its individuality and can 
be again separated from the mass. The Myxobacteriacete are charac- 
* Ann. de Micrographie, ix. (18D7) pp. 473-503. 
+ Biol. Centralbl., xviii. (1898) pp. 161-6 (4 figs.). 
% Technology Quarterly, x. (1897) pp. 410-20 (1 pi.). 
* Bot. Ztg., lv. (1897) 2 te Abt., p. 319. Cf. this Journal, 1895, p. 345. 
|| Ber. Deutscb. Bot. Gesell., xv. (1897) pp. 542-52 (1 pi.) Cf. this Journal, 
1 R 97, p. 154. § Cf. this Journal, 1897, p. 569. 
1898 2 A 
