Notes. 
151 
species in which these peculiarities occurred were Closterium lanceola- 
tum , Ktz., and C. striolatum , Ehrb., both fairly common species. 
A represents the appearance of one of the abnormal specimens of 
C. lanceolcitum. Towards the centre of the frond was an oval deep- 
green body, about 40 p by 30 /x, enclosed in a well-marked coat of 
cellulose. In the rest of the frond the green contents appeared to 
have undergone complete disorganisation ; the central row of choma- 
tophores had entirely disappeared, though the protoplasm was still 
tinged with green in places. Around the oval body it was quite 
colourless. Several examples of this structure were observed ; in 
some of which there was only one of these bodies, in others two, and 
they were then situated nearly symmetrically, one in each half of the 
frond. They corresponded almost precisely to sexually formed zygo- 
sperms of the species in form and size. 
A 
B 
Fig. 2. 
A similar appearance was represented by numerous specimens of 
C. striolatum ; only that here the numbers of the spore-like bodies 
varied from only one to four or five in the same frond, as represented 
in B. They were in this species quite spherical (as also are the 
zygosperms), their diameter varying between 20 and 40 /x. Here also 
the chromatophores had completely disappeared. In both species the 
hyaline vesicles at the extremities of the frond were unchanged, and 
displayed the usual Brownian movement of the particles contained 
in them. 
The suggestion naturally presents itself that these spore-like bodies 
are the resting or encysted condition of a parasite. The lowest 
organisms seem as liable as the higher ones to the attacks of parasitic 
fungi. These belong mostly to the orders Chytridiaceae and Monadi- 
neae, and have been observed in the Diatomaceae, Nostocaceae, 
