202 CHYTRIDIEE. 
GENUs 80. CHLOROCHYTRIUM. Coin. 
Plant endophytic; green, unicellular; cells globose, or some- 
what irregularly bi-, tri-, or multi-lobed; densely filled with 
chlorophyll, first dividing into large segments, and then these 
giving origin to innumerable pyriform zoospores, which escape 
through a tubular process. 
Chlorochytrium Lemnz. Cohn. Beitr. 1., 87. 
The zoospores, impinging on the epidermis of the duckweed 
at the junction of two cells, after germination commences a tube 
is produced, which, entering between the walls of the dissepi- 
ments, proceeds as far as the mesophyllic parenchyma, growing 
into the intercellular spaces, and forms either a globose, 
elongated, or irregular-shaped cell. 
Size. Adult cell 0--1 mm. diam. 
Wright in Trans. Roy. Irish Acad. xxvi. (1877), p. 18. 
Archer in Quart. Journ. Micr. Sci. xv. (1875), p. 104. 
Living in the thallus of Lemna trisulca, Westmeath (Ire- 
land). 
Cohn says of this species: “Its zoospores attach themselves to the 
thallus of the duckweed often in hundreds, They force their way 
through between the epidermal cells, assuming, as the foremost portion 
gets into the hypodermal tissues, a more or less figure of eight-shaped 
form: the foremost portion, getting into an intercellular space, dilates ; 
the portion that has not entered remains unexpanded, and forms a 
colourless nipple-like projection ; the portion within the thallus expands 
to many times its original diameter, sometimes dilating and filling up an 
intercellular space, at others distorting the subadjacent cellular tissue, 
and frequently itself becoming variously distorted. The cell wall becomes 
thicker, even laminated; the chlorophyll contents get dark and dense, 
and the cell becomes of a dark, nearly opaque green; sometimes starch 
granules are seen. The cell contents become segmented, breaking up into 
a number of pear-shaped zoospores, which escape through the nipple-like 
projection ; their actual exit was not seen, nor was the number or position 
of the cilia observed. Of the zoospores, many never succeeded in pene- 
trating the epidermis of the duckweed upon which they alighted, and 
such would remain as minute colourless pin’s heads on the surface of the 
Lemna. Some would linger within the mother cell, and might possibly 
be resting spores.”—A bstract by Prof. Perceval Wright, loc. cit. 
Plate LXXAXT, fig.9, Chlorochytrium Lemne parasitic on duckweed. 
Zoospores located in intercellular spaces x 600. Fig. 10, in a more 
advanced stage x 600. Fig. 11, free zoospores x 600. After Cohn. 
