



surface layer of the sea being so thick with them that 

 every bucket or bottle of water drawn at random brings up 

 multitudes. These swarms may be quite local, a few 

 miles away there may be none, or the surface fauna may 

 have quite a different constitution ; and moreover they 

 may disappear from a spot very suddenly, moving off to 

 another locality or sinking to a deeper layer of water. In 

 all probability these changes in the surface fauna have a 

 good deal to do with the movements of fish as it is well 

 known that the larger Copepoda are an important article 

 of food to some fishes, and even to some whales. 



At other times — frequently in winter — the surface fauna 

 in our district is chiefly composed of the crystalline worm 

 Sagitta ; and sometimes the sea over large areas is covered 

 with one or more species of the minute Dinoflagellata be- 

 longing to the genera Geratium and Peridinium. These 

 are known to serve as food for the Sardine off the French 

 coast, as many as twenty millions of Geratium tripos having 

 been calculated as being at once in the stomach of a Sardine ; 

 and no doubt they are equally important in connection 

 with our fisheries here. 



These various changes in the surface fauna which are 

 indirectly of great economic importance are not matters of 

 chance, but must all be due to a definite sequence of events ; 

 and the question is whether these events, i.e., the con- 

 ditions of the environment both animate and inanimate, 

 are too complex for us to determine, or whether we can 

 ever hope by accurate observations extending over some 

 years to be able to account for, to predict, and even to 

 regulate, the presence or absence in a particular locality of 

 the food, or the food of the food, of fishes at any given time. 

 At any rate the matter is well worth investigating, and I 

 would propose that definite observations of the meteoro- 

 logical conditions and the surface fauna be taken 



