140 HAECKEL 



so, not only on account of the courage it displayed 

 at the time, but also as a document relating to the 

 great controversy of the nineteenth century. It is 

 found on pages 231 and 232, partly in the text, 

 but for the most part in a note. Immediately 

 after giving the table of classification Haeckel goes 

 on to say : " I cannot leave this general account 

 of the relationship of the various families of the 

 radiolaria without drawing special attention to the 

 numerous transitional forms that most intimately 

 connect the different groups and make it difficult 

 to separate them in classification, to some extent." 

 It is interesting to note that in spite of our very 

 defective knowledge of the radiolaria it is neverthe- 

 less possible to arrange " a fairly continuous chain of 

 related forms." He would like to draw particular 

 attention to this, because " the great theories that 

 Charles Darwin has lately put forward, in his 

 Origin of Species in the Plant and Animal World 

 by Natural Selection, or The Preservation of the 

 Improved Eaces in the Struggle for Life, and which 

 have opened out a new epoch for systematic 

 biology, have given such importance to the 

 question of the affinities of organisms and to 

 proofs of continuous concatenation that even the 

 smallest contribution towards the further solution 

 of these problems must be welcome." He then 

 endeavours in the text, without any more theo- 

 retical observations, practically to construct a 

 "genealogical tree of the radiolaria," the first of 

 a large number of such trees in the future. He 

 takes as the primitive radiolarian a simple trellis- 



