ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
489 
Stem-leaves of Sphagnaceae.* — Dr. J. Roll adduces a variety of 
examples to demonstrate his statement that the stem-leaves may vary 
considerably in the same species of Sphagnum , and that trustworthy 
specific characters cannot in all cases be drawn from them. 
Algae. 
Algae as a cause of the Impurity of Water, f — Mr. G. W. Rafter 
publishes the results of a series of observations on Freshwater Algae, 
and their relation to the purity of public water supplies. He finds that 
a number of algae (and Schizophyceae) may contribute to render 
drinking water unpotable, producing a nauseous or “ fishy ” smell, 
generally due to the decomposition of their mucilaginous envelope, or 
of the starch or oil contained in their cells. In addition to the 
Schizomycete Beggiatoa , which has the property of withdrawing the 
sulphur from sulphates in solution, the following may be mentioned : — 
Cladophora , Vaucheria , Batrachospermum , Draparnaldia , Chsetophora, 
Volvox, Eudorina , Pandorina , Hydrodictyon , Palmella , Crenothrix , 
Oscillaria , and the diatoms generally, especially Meridion circulare. 
The desmids appear mostly to be innocuous. 
Inferior Algee.J — M. P. A. Dangeard dissents from Biitschli’s classifi- 
cation § of the Eugleneae, Cryptomonad ineae, Peridinieae, Chlamydo- 
monadineae, and Yolvocineae with the Flagellata, considering them to 
be true Algae, as is determined by their mode of life. 
Among the special forms described is Anisonema viridis [e] sp. n., 
belonging to the Palmellaceae, and nearly allied to Palmella hyalina. 
Among the Polyblepharideae, Pyramimonas tetrarhynchus is described in 
detail, characterized by having four projecting lateral wings and four 
cilia. To the same family belong Chloraster agilis and C. gyrans with 
five cilia. Among the Chlamydomonadineae a new genus and species 
Corhieria vulgaris is described, distinguished from all the other genera of 
the family by the posterior position of the nucleus and by the red-brown 
colour of the oosperm, which has also a doublo instead of a single 
membrane. 
Among the Yolvocineee, Pandorina is stated to have a Gonium-like 
early stage, which rapidly changes into a sphere. In Eudorina he finds 
green as well as yellow antherozoids. Under the Tetrasporeee, a new 
species and genus, Schrammia harhata is described, consisting of two- to 
eight-celled colonies inclosed in a cellulose-gelatine, rapidly becoming 
incrusted in calcareous water. The contents are blue-green, and it may 
belong to the Cyanophyceae ; it appears to be allied to Glceochsete 
Lagerh. 
In the non-sexual Pleurococcaceae we have a new genus and species 
Hariotina reticulata , apparently derived directly from the Volvocinese, 
resembling a Pandorina in the act of division. It consists of a number 
of green spheres, each consisting of from four to sixteen spherical cells, 
irregularly united together into a network by stout threads. It multi- 
* Bot. Centralbl., xli. (1890) pp. 241-5, 273-8. 
f Trans. Amer. Soe. Civil Engineers, 1889, pp. 483-557 (9 pis.). Cf. this 
Journal, 1889, p. 677. 
X Le Botaniste, i. (1889) pp. 127- 74 (2 pis.). Cf. this Journal, 1889, p. 95. 
§ Cf. this Journal, 1889, p. 776. 
1890. 2 m 
