STUDIES OF BRITISH FRESHWATER ALG^. 
43 
(e.g., 1904 and 1906) Synedra is more or less at a minimum, during 
the period in which Coccoiieis, for instance, is at a maximum ; and 
certain exceptional conditions may have led to their simultaneous 
dominance in June and July of 1905. 
Table showing relative abundance of the more important genera 
OF D 1 AT 0 MACE.E in the Fish Pond, Abbot’s Leigh, 1904-1 908 J 
Jan. 
Feb. 
Mae. 
Aprii 
May 
June 
July 
0 
< 
Sept. 
Oct. 
Nov. 
Dec. 
a904 
vc 
vc 
vc ! 
rc 
rr 
rr 
rr 
0 
r 
rr 
r 
rc 
1905 
VC 
vc 1 
vc ! 
r 
V 
rr! 
— 
r 
rc 
rc 
c 
c 
1906 
VC 
c 
rc 
rr ! 
r 
0 
rc 
rr 
rc 
0 
vc ! 
0 
1907 
rc 
0 
rc 
0 
— 
r 
0 
rr 
0 
r 
rr 
0 
1908 
vc! 
0 
rc 
rr 
rr 
0 
0 
0 
rr 
0 
0 
0 
e 
1904 
rc 
c 
vc 
rc 
rc 
rc 
rc 
0 
r 
r 
r 
rr 
1905 
vc 
c 
c 
rr 
r 
rr 
c 
rr 
rc 
rr 
rc 
c 
1906 
VC 
c 
rc 
rc 
r 
0 
rc 
rc 
rr 
0 
rr 
0 
1907 
— ? 
0 
rr 
0 
i 
rr 
0 
r 
0 
rr 
rc 
0 
J908 
c 
0 
rc 
rc 
rr 
0 
0 
0 
— 
0 
0 
0 
ri904 
vc 
c 
c 
rr 
r 
rr 
rr 
0 
rr 
r 
rr 
rr 
S s e 
^ ^ c^. 
0 0 .0 " 
1905 
1906 
c 
rr 
c 
vr 
c 
rr 
rc 
r 
rc 
vr 
rr 
0 
rr 
rr 
■ — 
r 
vr 
vr 
0 
r 
r 
r 
0 
1907 
— ? 
0 
— 
0 
— 
r 
0 
— 
0 
r 
— 
0 
^1908 
rr 
O' 
rc 
rr 
rc 
0 
0 
0 
vr 
0 
0 
0 
OB 
ri904 
rc 
rr 
rr 
rc 
c 
c 
c 
0 
ir 
rc 
r 
c 
1905 
— 
rc 
rc 
rc 
c 
vc 
vc 
vc 
c 
vc 
vc 
c 
s 
0 - 
1906 
rc 
c 
rr 
rc 
rc 
0 
c 
c 
rr 
0 
rc 
0 
0 
1907 
— ? 
0 
rc 
0 
r 
c 
0 
c 
0 
rc 
vr 
0 
0 
11908 
— 
0 
rr 
rc 
c 
0 
0 
0 
rr 
0 
0 
0 
• 1 
fl904 
vc 
vc 
vc 
c 
c 
rc 
rc 
0 
rc 
rr 
c 
c 
S OB 
1905 
vc 
c 
rc 
ri‘ 
r 
vc 
vc 
— 
— 
rr 
rc 
rc 
1906 
rc 
rr 
r 
rr 
r 
0 
r 
r 
vr 
0 
c 
0 
1907 
r? 
0 
rc 
0 
r 
rr 
0 
rc 
0 
— 
r 
0 
^1908 
vr 
0 
rr 
rc 
c 
0 
0 
0 
r 
0 
0 
0 
S 
[1904 
— 
— 
— 
vr 
vr 
— 
vr 
0 
— 
— 
— 
— 
g 
1905 
— 
vr 
— 
i 
vr 
— 
i 
vr 
rr 
rc 
c 
r 
1906 
rr 
— 
— 
i 
i 
0 
c 
rc 
vr 
0 
rc 
0 
1907 
— 
0 
rc 
0 
— 
— 
0 
vc 
0 
c 
ri' 
0 
11908 
rr 
0 
rr 
i 
r 
0 
0 
0 
— 
0 
0 
0 
CoGconeis, as already indicated above (p. 41), certainly attains its 
maximum development in the warm months of the year simultan- 
very common ; c — common ; rc = rather common ; rr = rather rare ; 
r = rare ; w’ = very rare; i = isolated ; o = no sample; — = absent. An exclama- 
tion mark indicates reproduction. We feel some doubt as to whether the 
January sample of 1907 was quite representative. 
