304 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
ceras and Lauderia, while in June Rhizosolenia and 
Guinardia predomutate. 
Dinoflagellata were abundant in 1910, and the 
records show that Ceratcwm was abundant all the year 
round, while Perzdinium is only present for the summer 
six months (April to October), with a maximum in May. 
The bearing of this and other cases of seasonal distribu- 
tion upon the question of ‘‘oceanic’’ and “‘ neritic ’”’ 
species 1s one requiring careful re-consideration. 
In many other details which have been dealt with 
in this investigation we find that the records for 1910 
agree with those of the preceding years, and support 
views that we have expressed in the previous reports. 
A number of other groups, and some leading genera, 
are discussed in the report; but we abstain for the 
present from drawing any further conclusions in view of 
our intention, after a further year’s records have been 
accumulated, of re-discussing fully the whole of the 
material available. We shall then have completed five 
‘ 
years of this “‘ intensive study ”’ of a small area, and it 
is our hope that the material then before us will be 
sufficiently extensive to enable us to formulate some 
definite, reliable conclusions as to the meaning of the 
plankton variations in this part of the Irish Sea. 
