Fig. 2. H.M.S. Challenger drawn byj. D. Milne from various sketches in the Challenger volumes. 



wonder that many other zoologists and botanists eagerly followed Miiller's 

 lead. Thirty years later a great deal had been learned, thousands of organisms, 

 both plant and animal, had been caught, studied and named according to 

 the Linnean system of nomenclature and the stage was set for the first and 

 still perhaps the greatest marine expedition of discovery. This was the 

 voyage of H.M.S. Challenger (Fig. 2) under the leadership of Sir John Murray, 

 which set out from Portsmouth in December 1872 for a voyage round the 

 world to investigate all kinds of life in the sea, plankton, nekton and benthos 

 from all depths from the Arctic to the tropical seas. She returned after four 

 years with an enormous wealth of material which was written up with 

 tremendous zest. The biological reports — the most extensive — were the 

 work of sixty-two authors who produced eighty-seven parts, bound in forty- 

 two larges tomes, in only nine years. Since then there have been numerous 

 major expeditions and some hundreds of minor expeditions, too many for 

 individual mention, examples are the great German Plankton Expedition 

 under Victor Hensen (the Hensen who first used the name 'plankton'), 

 the German Valdivia, and the Danish Dana. There are, too, the great 

 cruises of exploration by H.M.S. Discovery chiefly in the Antarctic, by the 



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