414 
MR. R. GURNEY ON THE CRUSTACEAN PLANKTON 
Table 1, showing composition of Plankton. The Lakes are arranged in 
Groups as in Pearsall, 1921, p. 276. Crosses enclosed in circles indicate 
that the species is occasionally^ found, but is not a regular member of 
the plankton. These species are not included in the total numbei's. 
, 
Gi-OLip 1. 
Group II. 
Group III. 
Group IV. 
1 
3 
2 
1 
w 
3 
® 
+ 
+ 
+ 
■i 
1 
a 
5 
a 
4 
+ 
+ 
® 
+ 
+ 
+ 
1 
1 
a 
5 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
1 
1 
1 
Q 

+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
a 
d 
7 
+ 
+ 
+ 
+ 
+ 
+ 
';3 
o 
O 
8 
+ 
© 
+ 
+ 
+ 
+ 
i 
.1 
9 
+ 
© 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
1 
5 
10 
+ 
+ 
.+ 
+ 
+ 
+ 
11 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
1 
]2 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
Sida crystallina 
Diaphanosoma brachyurum 
Holopedmm gibberum .... 
Daphnia hyalina s. str. . . 
„ lacustris 
,, galeata 
Cerwdaphma \P'^'e^fl<' , 
' 1 quadrangula 
Bosmina longirostris 
„ obtuairostris .... 
Polyphemus pediculus .... 
Bythotrephes longimanus . . 
Lcjitodora kindii 
Limnocalanus macriirus . . 
Diaptomus laticeps ...... 
,, gracilis 
Cycloim leuckarti 
„ abyssormn 
e 
+ 
+ 
+ 
+ 
+ 
® 
+ 
+ 
+ 
+ 
+ 
Number of species . . . . 
.5 
5 
3 
5 
7 
9 
7 
6 
1 
9 
6 
10 
8 
It should be noted further that collections have obly been taken from the 
shore of Buttermere, and that I have only a single collection from Grasmere? 
taken in September 1912. Species which are known to belong to the littoral 
fauna, such as Alonopsis elonyata, are omitted even when they have some- 
times been taken in the plankton. Chydorus sphcericus, which is often 
limnetic in central European lakes, is not found in the plankton of this 
district. 
It will be seen at once that the Crustacea do not conform to Dr. PearsalPs 
grouping, and indeed it is difficult to trace definite relationships at all. 
