22 THE MAMMALIA. 



not consider the difficulties arising from the endless 

 recurrence of the agreement of thousands of cir- 

 cumstances which are necessary for the production 

 of a definite organism, but declares this highly 

 improbable combination to be a law. That a sea- 

 feather of the southern ocean should ' originate ' 

 spontaneously without ancestors, and be precisely 

 like an individual in the northern ocean, which 

 owes its existence to the same unknown processes 

 without ancestors, shows such a degree of improba- 

 bility that it amounts to an impossibility. It is, in 

 fact, as improbable as that Adam originated out of 

 a clod of earth. The prophecy that the whole 

 edifice of the Darwinians would collapse, while the 

 theory of a universal law of development (which 

 assumes a number of independent pedigrees as its 

 basis) would rise up triumphantly instead, has not 

 yet been fulfilled. 



However, convergencies and repetitions have 

 been observed in abundance since then. In my 

 work on the Sponges, I have adduced special proofs 

 of how a series of convergencies the formation of 

 water-channels, form and disposition of microscopic 

 bits of skeleton and entire skeletons, root-like off- 

 shoots, tensions and other formations which are 

 defensive arrangements against the intrusion of 



