244 FOUNDERS OF OCEANOGRAPHY 



whenever a case of irregularity in distribution is observed, 

 to say that only proves that the conditions cannot have 

 been constant at that locality. If all these areas are ruled 

 out, then it becomes a question whether what remains of 

 the ocean is of any use to us as a basis for calculations as 

 to the planktonic contents of the sea either for practical 

 fishery purposes or for purely theoretical speculations. 

 Moreover, it must be remembered that the coastal waters, 

 which it is agreed are not homogeneous in character, and 

 where the plankton is very irregularly distributed, are just 

 the areas of most practical importance in connection with 

 the fishing industries. AU the great fisheries of the world 

 are carried on in coastal waters, so far as is known to us of 

 mixed character and containing a very irregularly distributed 

 plankton, 



P. T. Cleve has shown that in January, 1897, the North 

 Sea, our most celebrated North European fishery area, 

 contained at least five different types of plankton (named 

 from their characteristic organisms) — " Tripos " plankton, in 

 the centre ; " Halosphsera " plankton forming a belt around 

 that and stretching from Denmark to Scotland ; " Con- 

 cinnus " plankton, nearer each shore and extending down 

 the coasts of Holland and Belgium towards the English 

 Channel ; while " Tricho " plankton and " Sira " plankton 

 border the south of Norway and fiU up the Skagerak. 

 And a similar mixture of different types and quantities of 

 plankton will probably be found to obtain in other large 

 fishery areas — not to say oceans — when they come to be 

 adequately investigated. 



As another example of evidence of irregularity in distri- 

 bution of the plankton, take the results obtained by Dr. 

 Herbert Fowler in his expedition in the North Atlantic 

 in the summer of 1900 — a cruise which has thrown much 

 light upon the relations of oceanic plankton. Dr. Fowler's 

 results are valuable in demonstrating the varied composition 

 of the plankton from day to day in the open sea. His sixteen 



