128 Mr C. Warburton, On a new species of Spider. [Nov. 14, 
Peronospora, the extermination of the latter would involve the 
disappearance of the former. The Macrosporiwm does not attack 
the healthy plant. 
Only two kinds of insects, the onion thrips and the onion fly, 
were met with, and the latter on only one occasion. The thrips 
were not numerous and appeared to do little harm. They can 
easily be removed by application of a solution of iron sulphate, 
such as is recommended above. 
The onion fly may be dealt with by covering the bulb of the 
onion with a thin layer of earth. This prevents the fly approach- 
ing the bulb to lay its eggs. 
(2) On Alternation of Generations in Green Plants. By 
J. REYNOLDS VaizEy, B.A. 
The objects of this paper are to discuss the origin of Alternation 
of Generations in green plants, and to consider what effect the 
view of the origin of alternation of generations has on comparisons 
between the vegetative bodies of the oophyte and sporophyte of 
the same or different forms. 
Comparisons of the life-histories of Coleochwte, Oedogonium, 
Sphaeroplea, Ulothrix, Hydrodictyon, Pandorina and Chara, with 
that of the lowest mosses shew that in all these forms there 
is virtually alternation of generations. In the lowest forms the 
sporophyte is shewn to consist of a simple mass of cells produced 
by division of the oospore, each cell becoming sooner or later a 
spore which gives rise to the oophyte. Upon these comparisons it 
is suggested that alternation of generations arose from polyem- 
bryony, not, as according to Pringsheim’s theory, by a process of 
differentiation from a number of individuals which were both 
sexual and asexual. 
If this hypothesis is true, it is then pointed out that the 
sporophyte is a new body originating among the higher Algae 
and Liverworts, not genetically connected with the sexual body. 
Consequently the tissues of the sporophore cannot be homologous 
although they may be analogous with those of the oophyte. 
(3) On a new species of spider, with some observations on 
the habits of certain Araneina. By C. WARBURTON. 
The new spider was of the genus Linyphia, and nearly allied 
to Linyphia rufa Westr. from which, however, it was readily 
distinguishable by the structure of the male palpi, as well as by 
other peculiarities. 
