ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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nor cystids, but very peculiar conids. They are mostly ovoid in form, 
8-12 x 6-8 fx in size, thick- walled, and of an intense reddish-yellow 
colour, and are borne in chains of from 3 to 10. 
Protophyta. 
a. SchizopLyceae. 
Cell-contents of the Schizophyta.* * * § — Herr H. Zukal states that if 
filaments of Tolypothrix (e. g. T. lanata ) are examined in the autumn, 
the cells in the lower part of the filament are seen each to contain a 
large “ nucleus,'* which itself encloses a definite “ nucleole.” The upper 
part of the same filament frequently consists of a hormogone with 
oscill aria-like habit, the cells of which contain no trace of a “ nucleus.” 
By cultivation Herr Zukal established the fact that the so-called 
“nucleus” in the large cells rapidly divides into two, four, eight, &c., 
“ nuclei,” these constituting the so-called “ granules,” which have fre- 
quently been described as occurring in the cells, and that the so-called 
“ nucleoles ” are not true nucleoles, but nuclei, around which the proto- 
plasm has collected in the same way as it does round the nuclei in the asci 
of the Ascomycetes. The granules exhibit all the properties of nuclei in 
the position in which they place themselves in the cell, &c., though their 
micro-chemical reactions are difficult to determine, owing to the presence 
of the phycocyanin. He obtained evidence, however, that the cells of 
the Cyanophycese contain a cliromatophore coloured by phycocyanin, 
and a colourless cytoplasm, in which the nucleus, or more commonly the 
nuclei or granules, are imbedded. 
The cells of the Schizomycetes or bacteria contain bodies of precisely 
the same character as the nuclei or granules of the Cyanophycese. 
Nucleus in the Cyanophycese.f — M. P. A. Dangeard believes that 
he has detected a true nucleus in Merismopedia convoluta. Fixing with 
absolute alcohol and then staining with haematoxylin showed the 
presence of a central corpuscle occupying one-third or one-half of the 
cell, and strongly stained. It was usually spherical, but sometimes of 
irregular form or stellate, and in that case the substance was somewhat 
granular, in the former case homogeneous. No trace of a nucleole 
could be detected. 
Propagation of Diatoms by Germs.J — Sig. L. Macchiati records 
an observation of a specimen of Navicula elliptica , within the siliceous 
coating of which were inclosed four other individuals which he regards 
as germs ; they agree with the parent plant in every respect except their 
much smaller size : the transverse and longitudinal diameters were 
scarcely one-third of those of the inclosing specimen. 
Biology of Diatoms.§ — Dr. P. Miquel finds that a temperature of 
- 15° C. entirely destroys the vitality of diatoms, as well as of green 
* Ber. Deutsch. Bot. Gesell., x. (1892) pp. 51-5, and SB. K. K. Akad. Wiss. 
Wien, ci. (1892) pp. 801-27 (1 pi.). 
t Le Botaniste (Dangeard), iii. (1892) pp. 28-31 (1 pi.). 
% Bull. Soc. Bot. Ital., 1892, pp. 168-72. 
§ Ann. de Micrographie, iv. (1892) pp. 321-49. 
