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Relationship to the Mycetozoa and the Chytrideae . 
The genus Sorosphaera, Schrot. 
This genus is marked by the spores being collected into hollow 
spherical masses, enclosed by a common membrane. It is represented by 
the single species .S'. Veronicae , which causes swellings on the stems, leaves, 
or inflorescences of various species of Veronica. I have found this parasite 
only in V. Chamaedrys , although it is stated by Lagerheim to be found 
also in V. hederifolia and in other species. I have seen V. hederifolia 
growing in the immediate vicinity of diseased Chamaedrys plants, the 
former remaining quite healthy. Diseased Veronica plants are not com- 
monly met with, and can only be identified with the aid of the microscope. 
Tumours caused by eel-worms are indistinguishable to the naked eye from 
those caused by the Sorosphaera. These eel-worm tumours, which are 
much more common, I have seen on V. Chamaedrys and other species of 
Veronica. 
The cytology and life-history of vS\ Veronicae has been described by 
Maire and Tison (11) and by Blomfield and myself (1). The first-named 
authors, in a recent paper (14), confirm the opinion expressed by Blomfield 
and myself that the infection takes place at the growing apex of the stem. 
Winge (26), in his paper on ‘ Cytological Studies in the Plasmodio- 
phoraceae ’, in remarking on the akaryote stage of the organism, states 
that the karyosomes of the nuclei of the amoebae disappear at the close of 
the vegetative period of its life-history, and that subsequently no fresh 
karyosomes are formed. He is of opinion that the akaryote stage is formed 
by the bulk of the chromatin passing out from the nuclei into the plasma 
of the amoebae. He does not, however, consider that the organism is at 
any period devoid of nuclei, since some of the chromatin always remains on 
the site of each nucleus. Subsequently fresh nuclei are formed on the sites 
of the former ones ; these, however, contain no karyosome, and form the 
reproductive nuclei of the organism. This confirms the statement made 
in my paper on the cytology of S'. Graminis (25), that the reproductive 
nuclei occupied the same sites as the early vegetative ones. Osborn (20), 
however, in his paper on Spongospora , states that there is a total disappear- 
ance of the vegetative nuclei, and that the reproductive nuclei are formed 
de novo on adjoining sites. 
The genus Tetramyxa, GobeL 
This genus, which is represented by the single species T. parasitica , is 
characterized by the formation of spores in tetrads. Its life-history and 
cytology have been studied by Maire and Tison (14), who state that the 
nuclear phenomena are for the most part similar to those met with in the 
other genera, with the exception that no akaryote stage appears to follow 
the close of the schizont stage. They have, however, observed and figured 
R 
