On the Life-history and Cytology of Chlorochytrium 
grande, sp. nov. 
BY 
B. MURIEL BRISTOL, M.Sc. 
With Plates V and VI and two Figures in the Text. 
I N the year 1881 Klebs 1 published a paper dealing with the life- 
histories of a number of new algae belonging to the Protococcales, 
which he described as being nearly related to Chlorochytrium , Cohn. 
These new forms he assigned to three different genera which he named 
Endosphaera , Scotinosphaera and Phyllobium. Two years later, Borzi 2 
described still another new genus, Centrosphaera , belonging to the same 
group. Since 1883 very little work has been done upon these algae, 
possibly because of the difficulty of obtaining any of them in sufficient 
quantity to carry out adequate investigations, but more probably because 
the distinctions between the genera, as laid down by Klebs and Borzi, 
are in most cases so insignificant as to render their identification extremely 
difficult. 
The possession of a considerable quantity of living material, which was 
identified as most probably a species, of Centrosphaera , Borzi, therefore led 
Professor G. S. West to suggest in October, 1915, that a careful study of the 
life-history and cytology of this alga might possibly help to eradicate 
the confusion existing among these genera. 
The alga was originally taken from a dyke in West Yorkshire along 
with a number of other water plants. Owing to the necessity of following 
its complete life-history before a definite conclusion as to its identity could 
be established, it was placed in a small wide-mouthed glass bottle covered 
with a watch-glass to await an opportunity for further examination. Water 
was kept in the bottle to a depth of about an inch, and as evaporation took 
place tap-water was added. 
1 . Georg Klebs: Beitrage zur Kenntniss niederer Algenformen. Bot. Zeit., vol. xxxix, 1881, 
PP- 3 2 9-336. 
2 A. Borzi in Studi Algologici, Messina, 1883, pp. 87-97. 
Annals of Botany, Vol. XXXI. No. CXXI. January, 1917.] 
