320 transactions liverpool biological society. 

 General Conclusions. 



We do not desire to change in any material respect 

 the general conclusions that we arrived at in last year's 

 report. We may quote in particular one paragraph which, 

 with the exception of the final sentence receives further 

 confirmation from this year's work. It is as follows: — 



" We see no reason to modify our view that the spring 

 phyto-plankton seems to remain longer in northern 

 Scottish waters than it does in the Irish Sea. It probably 

 disappears more slowly some years than others, and it 

 certainly seems to be replaced more on some occasions 

 than on others by invasions of oceanic zoo-plankton. This 

 summer there seems to have been a well-marked invasion 

 of this character to the North of Mull, carrying even such 

 an Atlantic organism as Doliolum almost into the Sound 

 of Mull." 



In regard to the last sentence, Doliolum was present 

 in 1912, while this year not a single specimen was seen. 

 On the other hand the pelagic, oceanic Pteropod Limacina, 

 which was present in quantity in 1911, and was totally 

 absent from our Hebridean gatherings in 1912, was present 

 in great abundance this year (1913) in all the open waters 

 from Mull to the Minch, North of Skye. The occurrence 

 of these two pelagic organisms, Doliolum and Limacina, 

 may be regarded as equally affording evidence of an inflow 

 of Atlantic water, and that the one should be carried in to 

 certain waters one summer, and the other the following 

 year, may be of no general significance, but may simply 

 depend upon the abundance and distribution of these 

 organisms in the outer area at the time when the inflow 

 took place. 



We may repeat what we stated last year in discussing 

 the three kinds of sea-water, (1) Arctic, (2) Atlantic, and 

 (3) Coastal, which may enter or affect the British seas, as 



