06 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
is found to be a very suitable and handy boat for all such work 
within a few miles of the shore in ordinary weather. The coarse 
and fine standard horizontal nets used (of No. 9 and No. 20 
grades of millers’ silk, respectively) were towed, simultaneously, 
one on each side of the stern, and worked within a few feet of 
one another. They were frequently renewed, so as to be con- 
stantly in good condition. | 
The full results of the work have been written out in 459 
lists, analysed and synthesised into eight tables of statistics, 
and represented graphically by fifteen sheets: of curves, in 
some of which six or eight organisms (such as the prevalent 
Diatoms or Copepoda) are shown in the one diagram. It is 
hoped that all these data may be printed eventually, but in 
the meantime, for reasons of economy, we must be content to 
publish the following summary of the leading characteristics 
of the year’s work, with some conclusions bearmg on the 
connection between plankton and the sea-fisheries which 
naturally follow. 
In 1918 the sprmg maximum of the total plankton was 
again in May, when the month’s average haul was 85'8 c.c., 
and the largest individual catch 158 c.c., on May 9th. The 
Diatoms show a regular rise in the monthly average from 
65,000 in January to 26 millions in May, then a rapid 
decline to the minimum of over 13,000 in August, a second 
rise to over 319,000 in October, and finally, a fall to the winter 
condition at the end of the year—which, however, is not so 
low as the summer minimum. The curve of these monthly 
averages is beautifully regular and typical, with its greater 
vernal and lesser autumnal maxima; and it is noteworthy 
that Diatoms are present in greatest abundance when the sea 
is nearly at its lowest temperature, and are at their minimum 
in the warmest month of the year (see accompanying tempera- 
ture chart for 1918). The greatest individual number of 
Diatoms was over 73 millions in one haul on May 21st. . 
