Ig12.] N. ANNANDALE and S. Kemp: Kumaon Lakes. 133 
Both sponges and polyzoa were found in greater abundance 
than elsewhere on branches of trees growing towards the north end 
of the lake, in an area left entirely dry when the sluices are 
opened. Lophopodella cartert appeared to be equally abundant on 
the two occasions on which the lake was visited; but Pluwmatella 
allmant was only taken in October, 1907, and P. diffusa, P. 
emarginata and P. tanganytkae in May, Igtt. 
Most of the specimens of Ephydatia fluviatilis exhibited a 
peculiar external modification; growing on narrow twigs, their base 
necessarily covered a narrow but elongated surface; in consequence 
their growth was mainly in a vertical plane, the best developed 
having the form of a large cockscomb. 
Here, as in Naukuchia Tal and Malwa Tal, a small leech 
belonging to the genus G/ossos¢phonia' was found in considerable 
numbers. In May it was noticed that in small pools in the partly 
dried river bed at the north end of Bhim Tal, individuals of this 
leech were in the habit of attaching themselves to large water 
beetles belonging to the genera Hydrophilus and Cybister : as a rule 
to the former. The position chosen was invariably the apex of the 
dorsal surface of the elytra, where in some cases as many as four 
specimens were found. Leeches could not be discovered beneath 
the wing-cases and it is difficult to suggest any reason for the asso- 
ciation of the two forms, except that leeches attached to water- 
beetles must have a considerable chance of escape from pools that 
are drying up, owing to the fact that the beetles have the power 
of flight. The species of the genus Glossostphonia are known 
to feed chiefly, if not entirely, on soft-bodied animals, and in the 
present case it was clear that they were unable to penetrate the 
hard integument of the insects. Mollusca were abundant in these 
pools, but only to one specimen, belonging to the genus Limnaea, 
was a leech attached. 
In Bhim Tal itself no large water-beetles appeared to exist. 
Glossosiphonia was found under stones round the margin of the lake, 
frequently with young ones of a pale green colour attached to the 
ventral surfaces. At least three other Hirudinea were found to- 
gether with this form, one of them probably representing the genus 
Limnatis. In addition a small dark grey planarian was not 
uncommon. 
As regards the plankton the most notable feature on both 
occasions was the enormous abundance of a Ceratium; but whereas 
in 1go7 the form that occurred could be identified with C. 
longicorne, Perty, in May, 1911, the majority of the specimens 
agreed closely with Carter’s original figure of C. kumaon-nse. It is 
obvious that much research on the Peridiniaceae of the Indian 
lakes is necessary before any statement can be made as regards 
the limits of the ‘‘species’’—-even of those already recorded. 
1 Mr. W. A. Harding has kindly informed us that this species is closely allied 
to the British G. hetevodita but probably represents a form hitherto undescribed. 
It is perhaps specifically identical with a species occurring in Calcutta but not as 
yet found in association with beetles in that locality. 
