142 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



identical with forms we occasionally find in the Irish 

 Sea. 



Quite a number of samples of surface plankton have 

 been taken in limited areas of the Irish Sea on the same 

 day by the steamer, the Fishery officers, Professor 

 Herdman, and Mr. Chadwick in the course of this year. 

 The results are given on the following pages. Except 

 where otherwise mentioned, the collections were secured 

 with an ordinary open tow-net worked close to the surface. 



On January 3rd, a collection was taken off Blackpool 

 and another near the Liverpool Bar Lightship. These 

 places are about forty miles apart. The following are 

 the organisms found* in each : — 





Blackpool. 

 c. 



Liverpool Bar 



Rhizosolenia ahrubsolei 



.... . r. 



fr. 



r. 



Ceratium fusus 



Noctiluca 



fr. 



fr. 



r. 



Sagitta 



Copepoda 



Temora 



ab. 

 ab. 



c. 

 c. 



c. 

 r. 



Paracalann s 



Oithona similis 



c. 

 c. 



r. 



Oithona nana 



.... r. 

 r. 



— 



Pseudocalanus 



r. 



r. 



The difference here is very marked, thirteen 

 organisms occurring at Blackpool and only seven at 

 Liverpool Bar. Three out of the seven species of Copepods 

 are absent at the latter place. Samples taken more in 

 the open sea on the following day near the Liverpool 

 North-west Lightship and in Red Wharf Bay — places 

 about forty-five miles apart — gave the following result : — 



* ab. abundant ; c. common ; fr. frequent ; r. rare ; v.ab. very abundant. 



