170 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



represented the Diatoms ; both were scarce. A week later 

 Chcetoceros was absent, Coscinodiscus had become more 

 numerous and Biddulphia was found. Copepoda were 

 tolerably plentiful the week previous, and such forms as 

 Calanus and Anomalocera were quite conspicuous. Six 

 genera were then present. On September 17th the 

 Copepoda had almost disappeared. Only three of the 

 genera observed on the former visit were found, and these 

 were represented by a few individuals. 



We sometimes find that the pelagic life of the sea 

 undergoes great changes in a very short time. Organisms 

 that may be abundant one day are often quite absent on 

 the next, and collections taken in the same place on 

 successive days rarely give identical results. 



On August 22nd and 23rd the sea North of the Calf 

 Island was investigated, and the following organisms were 

 found : — 



August 22. August 23. 



Chsetoceros r. ... r. 



. Crab megalopa r. ... — 



Copepoda r. ... c. 



Paracalanus v.r. ... — 



Temora v.r. ... — 



Acartia v.r. ... — 



Oithona r. ... c. 



Oikopleura c. ... — 



Quantity of material 2 c.c. ... 1 c.c. 



The first visit gave a greater number of organisms 

 than the second. Copepoda, although very scarce on the 

 22nd, were represented by four genera. Next day this 

 group was tolerably common, yet only one genus was 

 noted. 



Collections taken off Niarbyl on August 27th and 

 28th and September 1st showed differences of various 

 kinds. 



