220 
water-lily house, April, 1902 ; forming the greater part of a green 
scum on the lake, July, 1902 ; amongst Sphagnum in Orchid 
house, September, 1902 ; plankton of Themed at Kew, August, 
1902. 
pc Nitzsch. 
P. pleuronectes, Nitzsch. Plankton of lake, April, 1902 
(Chodat !); plan kton of moat and pond, July, 1902; amongst 
other Algae i in side tanks of koc lend house, April, 1902 ; plankton 
of Thames at Kew, August, 190 
P. longicauda, Erb. Victoria regia tank, June, 1902; pond, 
September, 1902. 
