SEA-FISHERIES LABORATORY. 178 



siderable reduction in the number of organisms apparently 

 set in early in the month; Diatoms, Ceratium and 

 Coelenterata were entirely absent. The young lobsters 

 had also gone from this area, but a few occurred in 

 Carnarvon Bay and one in Lune Deep. The Protozoan 

 Noctiluca made its first appearance in this bay during 

 August, and was also diffused throughout the Irish Sea 

 at that time. Young Jaxea, young Squilla and Pontella 

 lobiancoi continued to be represented. Fish eggs and 

 young fishes had disappeared from all the coastal waters. 

 At Port Erin one or two eggs of the Norway topknot still 

 remained. Diatoms became more plentiful in other areas. 

 Representatives of four genera were noted between Red 

 Wharf Bay and Rhyl, one in the Ribble and two at Port Erin. 

 In September five gatherings were taken. The 

 number of organisms remained practically the same as in 

 August, but a great change had taken place in the con- 

 stituents of the plankton, not only here but all over the 

 area. The larvae of Crabs, Jaxea and Squilla had gone, 

 and also some of the copepods, including the species of 

 Pontella, Anomalocera, Labidocera, and a few others. 

 Twelve species of copepoda were present in August and 

 only seven in September. Diatoms, Ceratium and Coelen- 

 terata re-appeared, and small swarms of gasteropod and 

 lamellibranch larvae were met with. Diatoms had become 

 well diffused throughout the Irish Sea. Three genera were 

 represented in Cardigan Bay, four along the North Wales 

 coast, one at the mouth of the Ribble, Blackpool and 

 Port Erin. Three species of Ceratium were present in 

 every one of the areas examined, excepting Port Erin. 

 Coelenterata were uniformly distributed. A few zoea of 

 crabs (Porcellana sp.), and late megalopa stages of other 

 species were found along the North Wales coast and off 

 the Ribble. 



