Ii 4 INVERTEBRATE PALAEONTOLOGY 



older realization of the underlying uniformity that apper- 

 tains to all living things was, in some ways, of even 

 greater assistance towards understanding of vital pheno- 

 mena. But there is not yet any real knowledge of the 

 forces that drive, or the laws that guide, the stream of 

 organic progress ; a general view of faunas and floras, 

 recent and fossil, gives an impression of a mob locally 

 segregated into cliques rather than of a procession with 

 definite order and aim. It may be taken as certain that 

 the disorder is merely apparent the product of im- 

 perfect and restricted knowledge. Palaeontology gives 

 scope for longer and wider views than the Sciences that 

 deal with existing forms alone ; in fuller knowledge of 

 fossils lies the hope for discovery of the fundamental 

 laws of life. 



In the earlier parts of this chapter, analogies have 

 been made between individual and phyletic careers ; 

 comparison of the two kinds of " life-history " can be 

 amplified with profit. It may be assumed that the laws 

 that govern individual life are operative throughout the 

 organic world. Such an assumption, supported by 

 knowledge of the working of comparable laws, leads 

 logically to the suggestion that a clue to the nature of 

 vital principles may be found by study of the life-history 

 of any single organism. Whether the expression of the 

 laws manifested in the brief span of individual life is 

 simplified, or concentrated (with resulting complexity), 

 can be determined only by comparison with its extended 

 record in phylogeny. But, since every organism gives 

 some amount of phyletic recapitulation in ontogeny of 

 the matter of which it is built, it is reasonable to expect 

 that the manner and process of its living may bear com- 

 parable relation to the laws of evolution. " Know 

 thyself" may still be the oracular reply to a seeker after 

 biological knowledge. 



