ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
751 
In M. quadrifolia he states that the transition from the large initial 
cells into the long narrow cells of the plerome-cylinder is very gradual ; 
from the time when the initial cells are cut off, the three tissues, derma- 
togen, periblem, and plerome, are distinctly differentiated. The root- 
cap is formed from segments cut off from the base of the pyramidal 
apical cell. 
In Equisetum arvense there is no hypodermal layer as in Marsilea ; 
the endoderm divides into two layers at about the fifth or sixth segment, 
and these two layers are not further divided by tangential walls. The 
description of the mode of formation and division of the root-cap differs 
somewhat from that of previous writers. 
Fossil Plants of the Coal-measures.* — In his latest contributions 
to this subject, Prof. W. C. Williamson, after describing certain fossils 
from the Coal-measures belonging to the genera Pachiopteris , JRhizonium , 
and Lepidodendron, states his view that in the primeval Vascular Crypto- 
gams we find important histological and physiological phenomena to 
which no exact parallels are to be found amongst living plants. The 
development of the medullary area and the coincident annular expansion 
of the vasculo 'medullary cylinder, so characteristic of all the Carboni- 
ferous Lepidodendroid plants, he attributes rather to schizogenetic than 
to lysogenetic action. 
Muscineae. 
Braithwaite’s British Moss-Flora. — Part XIII. of this publication is 
devoted to the Splachnaceae, comprising the genera Splachnum (3 species), 
Tetraplodon (2 species), and Tayloria (2 species) ; the monotypic (E di- 
podium Griffithii, which represents the family CEdipodiacese ; the Funa- 
riaceae, comprising Discelium (1 species), Amblyodon (1 species), Nano - 
mitrium (1 species), Physcomitrella (1 species), Physcomitrium (2 species), 
and Funaria (6 species) ; and three monotypic genera of Bryacese, viz. 
Oreas, Stableria, and Leptobryum. It is illustrated by six beautiful 
plates. 
Characese. 
Antherozoids of Characese.f — M. W. Bijelajew has investigated the 
structure and development of the antherozoids in Gliara and Nitella, and 
his conclusions differ in some points from those of Guignard.J Imme- 
diately after the nucleus of the mother cell has attached itself to the 
wall, the anterior end of the antherozoid manifests itself as a filament 
springing from the nucleus ; from its attached end arise the two cilia. At 
the opposite end of the nucleus there is at the same time attached to it a 
somewhat stronger filiform structure, the posterior end of the antherozoid. 
The nucleus then also itself elongates, and becomes the middle part of 
the antherozoid. The cilia spring from the point of junction of the 
anterior end and middle portion of the antherozoid. 
* Phil. Trans. Roy. Soc., clxxx. (1890) pp. 155-68, 195-214 (8 pis.), 
t SB. Warschauer Naturf. Gesell., Sept. 27, 1889. See Biol. Centralbl., x. (1890) 
p. 220. X Cf. this Journal, 1889, p. 41 7. 
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