GO MAS TRO Y P'E 
À MALAY FORM OF CHLOROCOCCUM HUMICOLA. 473 
On a Malay Form of Chlorococcum humicola (Nüg.), Rabenh. By B. Murren 
Bristot, M.Sc. (Communicated by Prof. G. S. West, F.L.S.) 
(Prates 17 & 18.) 
[Read 21st March, 1918.] 
I. HISTORICAL. 
CHLOROCOCCUM HUMICOLA was first described by Nügeli in 1849, under the 
name Cystococcus humicola, Nüg.*, as a spherical unicellular alga completely 
saturated with chlorophyll, except for a single lateral coloufless space, and 
containing a single pyrenoid. He described its multiplication as being 
by non-motile gonidia set free by a splitting of the mother-cell-wall, but 
did not observe any motile cells in connection with the alga. In 1868, 
Rabenhorst f. identified the genus Cystococcus, Nüg., with that which Fries 
had deseribed, in 1825, as Chlorococeum, in which multiplication by biciliate 
zoogonidia had been observed ; and this alteration has been supported by the 
great majority of later botanists. De Toni ft, however, in 1889, included 
the genera Chlorococeum, Fries (1825), and Cystococcus, Nüg. (1849), in the 
genus Protococcus, Ag. (1824), with which he considered them synonymous. 
Wille’s recent researches§ on Prof. C. A. Agardh’s original specimens in 
the Lund Botanical Museum show, however, that Protococcus viridis, Ag., 
is identical with the alga later described as Pleurococcus Nägelii, Chod., and 
that De Toni’s diagnosis of Protococcus viridis, Ag., to include Chlorococcum 
humicola (Niig.), Rabenh, is quite wrong, since the formation of biciliate 
zoogonidia has been definitely established in this last species. 
Wille shows in the same paper that the alga described and figured by 
Meneghini, in 1842, under the name Chlorococcum Monas (Ag.), Menegh. ||, 
cannot be the same as Agardh’s Protococcus Monas, because Agardh's 
species contains no pyrenoids, whereas, both in the description and in the 
figure, Meneghini lays partieular stress on the clear spot in the periphery, 
by which only a pyrenoid can be intended. Wille suggests further that 
Meneghini's species was probably the same as Chlorococcum humicola (Nag.), 
Habenh. If this is so, and it seems quite possible, Meneghini failed to 
observe the great variation in size of the vegetative cells, and only an 
examination of Meneghini's original material could prove the truth of 
Wille’s suggestion; but, in any case, the specific name humicola has been 
* Nägeli, ‘Gattungen einzelliger Algen, Zürich, 1849, p. 85, tab. iii. E. 
T Rabenhorst, Fl. Eur. Algar. iii. 1868, p. 57. 
t De Toni, ‘Sylloge Algarum,’ 1889, vol. i. p. 699. 
§ Wille, N., * Algologische Notizen, xxii Christiania, 1913. 
|| Meneghini, J., * Monographia Nostochinearum Italicarum.” Aug. Taurin. 1842, S. 28, 
tab. iii. fig. 1. 
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