ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
235 
Van Henrck’s Synopsis of the Diatomacese.* * * § — An English trans- 
lation of this important work has appeared in advance of the original 
treatise in French. It makes up a volume of nearly 600 pp., illustrated 
by 35 pis. containing 917 figs., besides 300 inserted in the text. In 
addition to the systematic portion, it contains a full account of the 
structure, movements, multiplication, and reproduction of diatoms. The 
author regards it as an established fact that a substance passes from the 
cell-cavity through canals or pores in the silicified coat. 
Schmidt’s ‘Atlas der Diatomaceen-Kunde.’ — Hefts 52, 53 of this 
magnificent work, just published, contain 8 plates, Nos. 205-212, chiefly 
devoted to various species of the genera Surirella, Plagiogramma, and 
Navicula. 
Structure of Cyanophyceae.f — Prof. E. Zacharias confirms his pre- 
vious conclusion that the central body of the Cyanophycese differs in 
important points from the nucleus of other organisms. He now consi- 
ders it doubtful whether the central substance contains nuclein like the 
chromosomes. In Gloiotrichia pisum it is probable that the central body 
of the spore and of the cells immediately above it contains glycogen. 
The cell-protoplasm contains, at different stages, varying quantities of 
granules, which are chemically different from the central substance. 
The cell-division takes place without showing karyokinetic processes,, 
the disposition of the constituents of the central body being variable and 
without rule. The granules in the cell-protoplasm appear to increase in 
size and number when the cells are able to assimilate carbon. 
Development of Sphaerozyga.J — In addition to the ordinary Nostoc- 
form of Sphserozyga oscillarioides, Herr W. Schmidle finds, growing on 
Vaucheria sessilis , a form in which the cells which usually develope into 
resting-spores, remain in a purely vegetative condition, or become disor- 
ganised. Other cells, on the other hand, in the middle of the filament,, 
grow to a large size, and in these appear a number of very minute cells 
or spores. These do not swarm out, as described by Zukal in other 
Cyanophyceae, but escape through the gradual gelatinisation of the mem- 
brane of the mother-cell. In this condition the Sphserozyga resembles a 
colony of Aphanotliece. From other cells filaments arise which produce 
liormogones, and which are indistinguishable from a Calothrix. All 
intermediate stages occur between this and the Aphanothece-form. 
£. Schizomycetes. 
New Genus of Schizomycetes with Longitudinal Fission.§ — Mr. A. 
V. Jennings records the existence of a Schizomycete, Astrohacter Jonesii, 
found by Mr. A. C. Jones in fresh water. Its chief characteristic is 
that it divides longitudinally, thus eventually producing a distinctly 
stellate arrangement. Simple rod-like forms were observed, but more 
frequently V- or Y-shaped cells, resulting from longitudinal fission. 
After division the new segments become more and more widely separated 
* ‘ A Treatise on the Diatomacese,’ by Dr. H. Van Heurck, translated by W. E. 
Baxter, 1896. 8ee Bull. Soc. Beige de Microscopie, xxi. (1897) p. 24. 
f Rep. 66th Meeting Brit. Ass., 1896, pp. 1021-2. Cf. this Journal, ante , p. 156. 
X Ber. Deutsch. Bot. GeselL, xiv. (1896) pp. 393-401 (1 pi.). 
§ Rep. 66th Meeting Brit. Ass., 1896, p. 1012. 
R 2 
