EVOLUTION 23 



strongly with all we know of the present history of living 

 beings. 



Professor Huxley wrote in 1875 : " The only perfectly safe 

 foundation for the doctrine of evolution lies in the historical, 

 or rather archaeological, evidence that particular organisms 

 have arisen by the gradual modification of their predecessors, 

 which is furnished by fossil remains. That evidence is daily 

 increasing in amount and in weight, and it is to be hoped 

 that the comparisons of the actual pedigree of these organisms 

 with the phenomena of their development may furnish some 

 criterion by which the validity of phylogenic conclusions 

 deduced from the facts of embryology alone may be satis- 

 factorily tested." 



Palaeontology, however, as we all know, reveals her secrets 

 with no open hand. How can we be reminded of this more 

 forcibly than by the discovery announced scarcely three months 

 ago by Professor Marsh of numerous mammalian remains from 

 formations of the Cretaceous period, the absence of which had 

 so long been a source of difficulty to all zoologists ? What 

 vistas does this discovery open of future possibilities, and what 

 thorough discredit, if any were needed, does it throw on the 

 value of negative evidence in such matters ! Bearing fully in 

 mind the necessary imperfection of the record we have to deal 

 with, I think that no one taking an impartial survey of the 

 recent progress of palseontological discovery can doubt that the 

 evidence in favour of a gradual modification of living forms 

 is still steadily increasing. Any regular progressive series of 

 changes of structure coinciding with changes in time can of 

 course only be expected to be preserved and to come again 

 before our eyes under such a favourable combination of circum- 

 stances as must be of most rare occurrence ; but the links, more 

 or less perfect, of many such series are continually being 

 revealed, and the discovery of a single intermediate form is 

 often of immense interest as indicating the path along which 

 the modification from one apparently distinct form to another 

 may have taken place. 



Though palaeontology may be appealed to in support of the 

 conclusion that modifications have taken place as time advanced, 

 it can scarcely afford any help in solving the more difficult 



