294 
Proceedings of the Poyal Society 
Monday , 2 d March 1868. 
DAVID MILNE-HOME, Esq., Vice-President, in the 
Chair. 
The following Communications were read : — 
1. Observations on the Spores of Cryptogamic Plants, and on 
the Reproductive Process in some Algae and Fungi. By 
Professor Balfour. 
In this paper the author alluded to the spore as the ultimate 
germinating cell of cryptogamic plants. The true spore is the 
product of impregnation, but there are also bodies called spores 
which, so far as known, do not depend on the process of fertilisa- 
tion. Occasionally the term spore includes both the spore and the 
spore-case or sporangium. The structure of the spore was described, 
and its resemblance to the pollen grain, both as regards its anatomy 
and germination, was shown. Ciliated moving spores were con- 
sidered, and reference was specially made to the movements of the 
non-ciliated spores of Helminthora, which, when discharged, con- 
tinue to change their form for several hours like the Amoeba, 
becoming in turn oblong, pyriform, rhomboidal, &c., — lengthening 
and contracting, swelling at one point and shrinking at another. 
The germination of spores was considered. Some of them were 
shown to produce aprothallus, and were hence called Thalloid spores; 
while others had no prothallus, and were therefore Athalloid. In 
the case of the former, the prothallus was sometimes produced 
externally, as in ferns, and hence the spore was Exothalloid ; in 
other cases the prothallus was internal, as in Lycopods, and the 
spore was called Endothalloid. 
In all the great divisions of cryptogamic plants, bodies called 
Antheridia and Archegonia have been detected, — the former usually 
containing spermatozoids. 
The conjugation in Tyndaridea, Zygnema, and Mougeotia was 
then considered, and the function of a compound spore in some 
