SEA-FISHERIES LABORATORY. 169 



comparatively short, had distribution been uniform. We 

 find, however, that four of the constituents of the small 

 catch were absent at a spot five miles away. It is obvious, 

 then, that there was no uniformity in the plankton in 

 these areas on September 10th. 



A week later, September 17th, collections were taken 

 eight miles North- West of Port Erin and five miles West 

 of Cronk, which gave the following results : — 



8 Miles N.W. of 5 Miles W. 

 Port Erin. of Cronk. 



Biddulpliia r. ... r. 



Chsetoceros — ... r. 



Coscinodiscus fr. ... r. 



Ceratium tripos fr. ... c. 



Sagitta r. ... — 



Autolytus — ... r. 



Copepoda r. ... c. 



Centropages r. ... r. 



Anomalocera — ... c. 



Acartia r. ... r. 



Oithona r. ... r. 



Oikopleura — ... fr. 



Sprat eggs — ... r. 



Quantity of material 05 c.c. ... 3 c.c. 



The difference in the constituents and the quantity of 

 plankton taken are well marked in this instance. The 

 distribution was probably more uniform than on September 

 10th, as only one of the organisms in the small collection was 

 absent from the larger one. The first station in the above 

 list is about three miles East-North -East of the area, nine 

 miles West-North-West of Port Erin, visited on September 

 10th. A. comparison of the plankton taken at these two 

 places on the dates given shows that considerable changes 

 had taken place in the course of a week. The amount of 

 plankton in the water was about the same on the two 

 dates. On September 10th Chcetoceros and Coscinodiscus 



