224 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Amongst the Diatoms, in spring, species of 

 Chaetoceras were in much greater abundance than usual 

 this year, and in autumn Biddulpliia , Thalassiosira and 

 Chaetoceras were greater in amount than in any of the 

 previous years of our study at corresponding times. 



In Conclusion. 



Each additional year's work tends to confirm us in 

 our view that, although there is a natural sequence in the 

 distribution of the plankton throughout the year, and 

 although there is a certain constancy in the maxima and 

 minima for particular groups and even species, still the 

 sequence is liable to disturbance and the maxima are 

 affected both in time and in amount by surrounding 

 conditions. This leads to the numerous variations which 

 we have had to record from year to year. 



Moreover, even when some constituent of the 

 plankton is most abundant, its distribution may be 

 irregular, in streaks or in patches, so as to destroy any 

 such uniformity as would justify small samples being 

 taken as representative of wide areas. 



We are not yet prepared to make the promised 

 collation and comparison of our records for the five years, 

 that was referred to in the last Report. We shall hope 

 to do so in a final part next year. 



