ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
837 
subsequently attacking the spongy parenchyme, but is very rarely 
found in tbe epiderm ; the plasmode, when young, is very difficult to 
distinguish from the protoplasm of the cell. The formation of spores 
has not yet been observed. 
The same authors also* * * § trace a disease which is very destructive 
to the vineyards in California, and which is known to some growers 
under the name of “ black measles,” to the attacks of another species 
of Plasmodiophora, for which they propose the name P. californica. 
It causes an irregular discoloration of the leaves, and finally disease 
in the stem and roots. 
Trichia.f — Herr A. Scherffel gives new diagnoses of the following 
species of Trichia, viz. T. chrysosperma, affinis, scabra, and Jachii , and 
points out the polymorphism that may occur within the same species, 
even in the microscopic structure. The form and dimensions of the 
tubes of the capillitium are more constant than their finer sculpture ; 
while the finer sculpture of the spore-membrane is of great constancy. 
The best specific characters are, therefore, iu the opinion of the writer, 
to be derived from the spores. 
Lindbladia.J — According to Mr. G. A. Eex, all the American forms 
of this genus of Myxomycetes belong to one species, L. ejfusa. He 
considers that although the two genera Lindbladia and Tubulina , which 
make up the order Liceace®, approach each other, having apparently 
been developed along similar lines, they nevertheless have probably 
arisen from independent, and, perhaps, widely separated points of origin. 
Protophyta. 
a. Schizopliycese. 
Structure of the Phycochromacese.§ — Herr G. Hieronymus has 
investigated the structure of the Phycochromace®, especially in relation 
to the nature of the peripheral colouring substance and of the central 
body ; the genera specially examined were Chroococcus , Gloeocapsa , 
Aphanocapsa , Clathrocystis, Aphanothece, Hypheothrix, Oscillaria, Phor- 
midium , Hydrocoleum, Symploca, Nostoc , Anabsena, Spheerozyga , Aphani- 
zomenon , Rivularia , Scytonema , Tolypothrix , Hapalosiphon, and Stigonema. 
With reference to the green peripheral layer, the author comes to 
the conclusion that it is of the same nature as the chromatophore of the 
higher plants, though not identical with it. Fibrill® and grana are 
both present, but do not form a connected whole. The layer consists of 
a comparatively small number of nearly parallel but rather distant 
fibrillse, hence the pale colour, and this number may even be reduced to 
one. There is no true honeycomb-like structure, as described by 
Biitschli |j in diatoms. 
The central body of the Phycochromace® differs from the cell- 
nucleus of the higher plants in several important points. It is of much 
looser structure, is not entirely closed, and possesses no true nuclear 
* Op. cit., cxv. (1892) pp. 67-9. 
t Ber. Deutsch. Bot. Gesell., x. (1892) pp. 212-8 (4 figs.). 
j Bot. Gazette, xvii. (1892) pp. 201-5. 
§ Beitr. z. Biol, d, Pflanzen (Cohn), v. (1892) pp. 471-95 (2 pis.). 
|| Cf. this Journal, 1890, p. 497. 
