66 
MINUTE PARASITIC ALG^. 
Dr. Perceval Wright has recently communicated two papers to 
the Royal Irish Academy,^ on new species of minute Algae, to 
which we desire to direct attention. In the first paper a very 
explicit description is given of the two species of Chlorochytrium, 
botli of which have been found in Ireland — the one, Chlorocliy- 
trium Lemnce, a bright emerald green Alg^, living as a parasite 
in the intercellular spaces of the parenchymatous tissue of Lenina 
trisulca ; and the other species discovered by himself, living in the 
thalliis of various species of Schizonema, Polysiphonia, &c., 
which has been dedicated to Professor Cohn. The descriptions of 
genera and species are thus given : — 
Chlorochytrium. CCohn.) 
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 liemnae. (Cohn.) 
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 dissepiments, 
proceeds as far as the mesophyllic parenchyma, growing into the 
intercellular spaces, and forms either a globose, elongated, or irre- 
gular-shaped cell — the diameter of the adult cell about 0*1 mm. 
Living in the thallus of Levina trisulca, 
Chlorochytrium Cohnii. (Wright.) 
The zoospores impinging on the fronds of several species of 
marine Algse, quickly assuming a figure-of-eight form, the lower 
sphere growing into the frond, and rapidly assuming comparatively 
large dimensions, the upper sphere remaining as a tube-like neck 
portion to the larger mass. On the cell arriving at an adult stage, 
the whole of the green protoplasmic contents divide into a number 
of from ten to thirty, nearly circular zoospores, which escape 
through the neck-shaped portion. 
Living in the thallus of various species of Schizonema^ Polysi- 
pliona, &c. ; also on Infusoria found at Howth. 
Although there is some difference in the process of the forma- 
tion of the zoospores, and the occurrence of large and small zoo- 
spores, between the latter species and the original diagnosis of the 
* “On a new species of Parasitic Green Alga belonging to the Genns 
Chlorochytrium of Cohn;” and “ On a Species of Rhizophydium Parasitic 
on species of Ectocarpus, with notes on the fructification of the Ectocarpi.” 
By Edward Perceval Wright, M.A., M.D., F.L.S., Prof, of Botany in the 
University of Dublin, in the “ Transactions of the Boyal Irish Academy,” 
Vol. xxvi. (1877). 
