TABLE XVII
a. A Comparison of the Increase in Pdycelis Numbers with those of Dugesia lugubris plus Dendrocoelum lacteuni .
b. The Numbers of Polycelis in the Pnesence and Absence of Dug. lugubris plus Dend. lacteum.
a
Calcium mg/litre
__
>40*0
Dug& + Dendrowelum
0
5 *6
36.5
46.4
141.6
144.2
Species
<2*5
2+5-0
5.1-10.0
10.1-20.0
20.1-40.0
Total Polycelis
30.7
104.7
136.3
250.0
209.0
222.3
b
198
289
224
-
Total Po1ydi.a when alone
-
-
Total Polyw1i.a when others present
-
-
68
213
190
222.3
Triclad populations recorded aa number collected per hour averaged for lakes in each calcium category;
a dash means no lakes in that category.