158 



TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Ceratium tripos 



Noctiluca 



Sagitta 



Crab zoea 



Crab megalopa . 

 Copepoda 



Centropages . 



Temora 



Anomalocera . 



Acartia 



Oikopleura 



Off Blackpool, 

 c. 



Entrance 



to Ribble. 



r. 



c. 



r. 



c. 

 r. 



r. 

 v.ab. 

 v.ab. 



v.r. 



r. 



v.r. 



r. 



v.r. 



r. 



v.r. 



r. 



— 



r. 



— 



r. 



Noctiluca, though tolerably common off: Blackpool, 

 was almost absent a few miles away. On the other hand, 

 the collection taken at the entrance to the Ribble consisted 

 of little else than Zoea and Megalopa of crabs. Off 

 Blackpool the former was fairly numerous, and the latter 

 very scarce. 



The North Wales area was traversed again on August 

 10th, and tow-nettings were taken in Llandudno Bay, off 

 Puffin Island and in Red Wharf Bay. These collections 

 differed from each other, and also showed great changes 

 when compared with the plankton found four weeks 

 previously. 



Rhizosolenia ... 



Ceratium tripos 



Noctiluca 



Pleurobrachia 



Sagitta 



Crab zoea 



Crab megalopa 



Copepoda 



Temora ...... 



Centropages , 

 Acartia 



Oikopleura 



Weever eggs ..., 



ndudno 



Off Puffin 



Red Wharf 



Bay. 



Island. 



Bay. 



— 



r. 



r. 



v.ab. . 



— '.'. 



v.ab. 

 r. 



r. 



c 



r. 



— 



r. 



r. 



— 



r. ' 



r. 



— 



r. ' 



r. 



— 



r. 



r. 



— 



— 



r. 



The plankton in Llandudno Bay was practically 

 composed of Noctiluca. In Red Wharf Bay similar 

 conditions prevailed, but the Noctiluca was mixed with a 

 few other organisms. It will be noted, too, that 

 Rhizosolenia was apparently just making its appearance. 



