288 HAECKEL 



on the floor of the ocean, from a certain coast-limit 

 into the deepest parts, is composed for the most 

 part of the microscopically small shells of little 

 marine animals. The living creatures that form 

 these shells swim in the water of the ocean, partly 

 at the surface and partly at various depths beneath 

 it. When they die the little hard coat of mail 

 sinks to the bottom, and as there are millions upon 

 millions of them living in the sea, thick deposits 

 are gradually formed at the bottom that consist 

 almost entirely of these microscopic shells. The 

 animals in question are primitive little creatures 

 consisting of a single cell, of the type that Haeckel 

 has called " Protists." Even in Ehrenberg's time 

 it had been noticed that amongst the shells in the 

 deep-sea mud there were, besides chalky shells, a 

 number of graceful flinty coats that clearly pointed 

 to the radiolaria. The Challenger expedition now 

 made the great discovery that vast fields at the 

 floor of the ocean, especially of the Pacific, were 

 covered almost exclusively with these flinty shells. 

 It was seen at once that the few hundred species 

 of radiolaria that had hitherto been described by 

 Haeckel and others were only a very small part of 

 the masses of radiolaria found in the ocean. The 

 specimens of the deposits which were carefully 

 preserved and brought home by the Challenger 

 contained such an immense number of unknown 

 species with their flinty shells faultlessly preserved, 

 that it was necessary to reconstruct the whole of 

 this wonderful group of animals. And who could 

 be better qualified for the work than the man 



