OF SOME NORTH WORCESTERSHIRE POOLS. 427 
| E - 
id 3 Gla 88 28 8 7^ a 
ORB 5 |5 £a EX dà E 8 | 
o = 2 = as) =. (cm Ay 
| ә 5 Б н UE Ок = wo - 
o | = = wo) we = ES 5 
| > 8 Е s БЕ Ес d ра © 
= S| 2 S ае кн = ам = 
| m a aA Zo ж 7 ж Щщ > 
Temperature, 9 C. ...... 15 75 1575 — | 165 165 1873 190 180 — 
| | | 
Curonornyckg (cont.). | | | | 
Tetraédron tetragonum (Nag.), Hansg.... ...  ... eso г. rrr. 
Тетаятит staurogenieforme (Хеһгой,), | 
Chodat ....... sess у fe ee рев г. | 
Dictyospherium pulchellum, Wood ...... ... m bes 2. wee э. es e c. 
Pediastrum duplex, Meyen................... c. r. e m 2. ОИ e г. | 
—— Boryanum (Turp.), Menegh. ......... | ос. e. ... т. ссе, € r. ... ro 
Cœlastrum sphæricum, Nig. ............ ese de | Rb ee ш ee | PP | 
cambricum, Archer ....... TERR e 3. esl | TIT. 
Geminella interrupta, Turp. ............... ... wee | eae сс. | | | | 
Staurastrum polymorphum, Bréb, ......... ш... р... | се. | | | 
- crenulatum, Мар... ... vee dos се. | | | 
Cosmarium reniforme (Ralfs), Arch. ...... | гг. |... г. г. | | 
granatum, Већ... Г... m с. с. | 
— Botrytis (Bory), Menegh. ............ |... e ... с. | 
—— Meneghinii, Bréb. п... уз se рг | 
Closterium cornu, Ehrenb. .................. boe А ... | rrr. | | 
—— Leibleinii, Kütz LS Ке el rrr, | | | 
Pleurotenium Trabecula (Ehrenb.), Nig. г. | | | 
| | | | 
| | | 
PERIDINIE®. | | | 
| 
Peridinium auglicum, ©. S. West ......... | e 2. Ке e m -. CC. | 
Ceratium Hirundinella (О. Е. Müller) | | | 
Schrank ннн I |. шй... poe ee Ce. се, | | 
IV. DISTRIBUTION ОЕ ALGA FLORA. 
As only one collection was taken from each pool, it is not possible to make 
any general statement concerning distribution. There are, however, one or 
two points of interest arising out of the observations :— 
(а) The presence of Bacillarieæ other than Asterionella is probably due 
to the occurrence of weeds, through which the plankton-net was 
unavoidably drawn. Thus the greatest number of diatoms was 
collected in Podmore and Island Pools, where weeds were plentiful. 
The remaining pools were practically free from weeds in the area 
from which plankton was taken. They yielded no diatoms except 
Asterionella. 
(b) The presence of Pandorina and Eudorina in the plankton appears to 
be correlated with comparative purity of water. It was found that 
these organisms occurred in pools through which a stream of some 
streneth ran, and which were either surrounded by fields or were 
of such size that the presence of a few houses would not seriously 
