424 МВ. В. М. GRIFFITHS ON THE AUGUST HELEOPLANKTON 
either rare or not commonly found in the plankton of large lakes were 
present. As no pool examined had an area of more than twenty acres, 
true plankton was not found. A large number of forms are derived from 
the benthos, and forms exclusively found in true plankton are rare. 
II. DESCRIPTION or Poors. 
1. Нигсой Pool. 
Area eighteen acres. This pool is the largest and deepest in the district. 
A strong stream flows through it, and the overflow runs into Podmore Pool, 
from thence to Broadwaters Pool, and eventually to the River Stour. The 
water is bounded by open pasture-land on one side and a wood on the other. 
At the lower end is a strong embankment, on which is a large paper-mill. 
There are no weeds in the centre, but around the sides and at the upper end 
there are quantities of Typha angustifolia, Nymphea lutea, and Polygonum 
amphibiun, 
2. Podmore Pool. 
Area eleven and a half acres. The pool is shallower than Hurcott, and is 
considerably silted-up at the upper end. It is surrounded by pasture-land. 
Weeds are rather plentiful; some oceur in the middle on a submerged bank. 
The stream-current is not very marked. Typha angustifolia is found at 
the upper end, and. Myriophyllum and Potamogeton are plentiful round the 
sides, 
3. Broadwaters Pool. 
Area nine and a half acres. The pool is not deep, and is divided into: 
three parts by embankments, each of which is pierced by tunnels. The 
water is surrounded by pasture-land and gardens. Мутр/еа and Nuphar 
are very plentiful. 
4. Island Pool. 
Area two acres. This pool lies in а small stream-course that reaches the 
River Stour. The water is shallow, owing to silting, and abounds with 
Myriophyllum in every part. The pool is surrounded by fields. 
5. Spring Grove Upper Pool. 
Area half an acre. The pool is one of three forming an ornamental lake 
in a private park. Itis fairly deep. Itis much shaded by large trees and 
is surrounded by grass-land. A little Polygonum amphibium occurs on the 
sides and in the middle. The water is derived from springs and flows into 
the Lower Pool. 
6. Spring Grove Lower Pool, 
Area seven acres. The pool is long and marrow and has two large 
