358 SECTIONAL TRANSACTIONS.—K. 
processes on the British coast illustrated by the Humber, the Yare, and Chesil beach. 
The same processes act on a greater scale on continental coasts. Coal formed on tidal 
lands. Newly formed tidal lands usually more extensive than the areas lost to 
the sea. E 
(c) Prof. R. H. Yarr. 
(d) Dr. VaugHAN CoRNISH. 
(e) Dr. E. J. Satissury.—The Succession Phenomena of Tidal 
Lands. 
The nature of the succession changes and their relation to time and other factors. 
General conclusions with regard to the succession and their significance with respect 
to the serial sequence of plant communities in general. 
(f) General Discussion. 
6. Dr. M. Knigur.—A Study of the Life-history and Cytology of certain 
species of Hctocarpus. 
The paper deals with certain morphological features of four species of Hctocarpus, 
and demonstrates the dependence of these features on variable external conditions. 
The preparatory cytological changes and the relations in time and space governing 
the production of unilocular and plurilocular sporangia are dealt with, and the fate 
of released zoospores is indicated. The critical points in the life-history—zeduction 
division and fusion—are established and the question of alternation of generations 
for the species is discussed. The results of certain tentative cultural experiments are 
also included. The latter part of the paper treats of the sexual or asexual nature of 
the two types of sporangia. 
7. Dr. HE. M. Detr.—Sexual Reproduction in the genus Bifurcaria, 
Stackh. (=Pycnophycus, Kiitz.) 
There are three species of Bifurcaria (Stackh.), two of which are S. African and one 
European, the latter occurring as far north as the S.W. coasts of England. These 
three species have been figured, but little is known of their life-history. Externally 
very similar, the reproductive organs show well-marked differences, including variation 
in the number of eggs to the oogonium, in the liberation of the oogonia, and probably 
also in the germination of the oospore. 
In P. brassiceformis (Kitz) the oogonia remain attached for some time to the mouth 
of the conceptacle, in a manner hitherto only described for certain Japanese species of 
Sargassum and Cystophyllum. Observations are also made on periodicity in the 
production of fertile shoots in the English species P. tuberculatus (Kiitz). 
AFTERNOON. 
8. Mr. B. Barnes.—A Contribution to the Morphology and Physiology 
of Acmosporium, Corda and Lachnea, Fries. 
ee) oe a ee ey 
Po * ieee 
It has been shown that a species of Lachnea has a conidial stage which falls into 
the genus Acmosporium. 
There is evidence that the appearance in culture of one or other of the stages is in 
part determined by the composition of the medium, and in part by the amount of 
light supplied to the culture. 
An account is given of the morphology of the two forms, with special reference 
to the development of the conidia and apothecia, and to the mycelial fusions which 
occur. 
As both forms have been repeatedly obtained from a single conidium, there is no 
reason to think that the fungus is heterothallic. 
9. Mr. G. Tanpy.—The Cytology of Pyronema domesticum, Sacé. 
The development of the sexual organs, the entrance of the male nuclei and their 
subsequent behaviour are described. Evidence is produced of the occurrence of 
nuclei in pairs at all stages. 
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