GROWTH OF IDEAS 289 



who had already made a name by his study of the 

 radiolaria, Haeckel ? 



When the English Government came to publish 

 the results of the Challenger expedition in a 

 monumental work (of fifty volumes), he was 

 entrusted with the work on the siphonophores, the 

 3orneous sponges, and all the radiolaria in the 

 sollection. For ten years, from 1877 to 1887, 

 Haeckel devoted every available hour to the 

 work of selecting the radiolarian shells with his 

 microscope from these specimens of the deep-sea 

 deposits, and naming, describing, and drawing the 

 new species. When he began his task 810 species 

 3f radiolaria were known to science. When he 

 3ame to his provisional conclusion, ten years 

 ifterwards, though his material was not yet 

 exhausted, there were 4,318 species and 739 genera. 

 They are described in the splendid work that he 

 wrote for the Challenger Keport. It consists of 

 jwo volumes of text (in English) with 2,750 pages 

 ind 140 large plates, with the title, Report on the 

 Radiolaria collected by H.M.S. Challenger. In 

 ]he preparation of these plates (and in the illus- 

 tration of all his later works) he had the very 

 /aluable assistance of the gifted Jena designer and 

 ithographer, Adolph Giltch. A good deal of new 

 nformation with regard to the living body of the 

 'adiolaria had come to light since 1862. In 

 particular it had now been settled beyond question 

 ihat they consisted merely of a single cell. There 

 tfas, therefore, a good opportunity of reconstructing 

 )he Monograph of 1862 with the new and more 



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