The Peri diniece of Sutton Park, Warwickshire. 181 
A BIOLOGICAL INVESTIGATION OF THE PERIDINIEAE 
OF SUTTON PARK, WARWICKSHIRE. 
By G. S. West, M.A., D.Sc., F.L S. 
[Text-Figs. 20—26J. 
ITTLE is known of the Peridinieae of the midlands of England, 
or indeed, of any of the low-lying parts of the country, 
although those of mountainous areas have been to some extent 
investigated. I have been engaged since October, 1906, in making 
a more or less continuous series of observations on the general 
periodicity and life-histories of the Algae which occur in that fine 
stretch of primitive country to the north-east of Birmingham known 
as Sutton Park. Some of these observations have now proceeded 
far enough to render publication of certain facts advisable, and the 
present account of Peridinieae is sufficient to show that there are 
probably many interesting freshwater members of this group in the 
less elevated areas of the British Islands. 
The species of Peridinium which is generally recorded as 
common in the ponds and pools of flat countries is P. tabulation 
(Ehrenb.) Clap, et Lachm., but I have found no trace of this 
organism in either Warwickshire or Worcestershire. 
In all, seven species of the Peridinieae have been observed in 
the pools and bogs of Sutton Park. Only one of these— Gleno- 
dinium uliginosum —is a bog species, occurring among submerged 
Sphagnum , the other six having been found exclusively in the 
helioplankton of Bracebridge Pool, a sheet of water of rather more 
than sixteen acres. Three of these, Peridinium aciculiferum , P. 
anglicum, and P. cinctum. var. Lemmermanni, are among the 
dominating constituents of the plankton of this pool at certain 
seasons of the year, although I have found no trace of any of them 
among the weeds at the margins. 
I. —Glenodinium uliginosum, Schilling. 
Although up to the present unrecorded for the British Islands, 
this organism is probably more generally distributed in British 
freshwaters than any other member of the Peridinieae. It is of very 
rare occurrence in the waters of pools and lakes, but may often be 
found in great abundance in bogs and boggy ditches, even up to an 
altitude of over 2,000 feet. 
