7A TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
August, and September. The following are some of the 
more important of these :— 
April 9—Pseudocalanus elongatus ... 16,000 
- .9—Temora longicornis ... SSG 
23—Calanus helgolandicus cv: Mb ESO 
24—Acartia clausi... to sae OO 
Aug. 18—Oithona similis co ..« 14000 
17— i, + i! ... 25,000 
24—-Acartia clausi ae ... 29,000 
27— ,, ee a ... 24,700 
29—Pseudocalanus elongatus ... 28,000 
Sept. 4—Acartia clausi BA ... 23,600 
4-—Pseudocalanus elongatus ... 36,000 
12— fe 93 ... 83,600 
18— ; 3 ... 25,000 
20—Oithona similis wt oe AO TO 
These also bear out the idea of maxima in April and 
in autumn, the latter being the more important one; in 
both cases they follow the phytoplankton. As a rule, a 
haul rich in Copepoda has few Diatoms, and wice versa, 
but the Copepoda do not, like the Diatoms, present great 
maxima and marked depressions. Mven when both groups 
are present in the plankton we frequently find that they 
are in different zones; for example, in some April hauls 
in 1907 the Diatoms were markedly on the surface and 
the Copepoda below, while later in the year these positions 
were reversed. 
The distribution of particular Copepoda (Calanus, 
Anomatlocera, Muicrocalanus, Pseudocalanus, Centropages, 
Temora) have been followed separately, and some of 
these form interesting studies. Calanus, Pseudocalanus, 
Centropages, and Temora are present throughout the 
year; Anomalocera appears in our district im spring; 
Microcalanus in late autumn. 
The Diatom fauna made its appearance again in 
September, 1907 (fig. 21). The two surface nets on 
September 12th show very large numbers of Diatoms, 
