WHAT IS EVOLUTION? 33 



of the oysters, which have continued from the Carbo 

 niferous age to the present, and that of the scorpions, 

 which have continued from the Silurian, in both cases 

 with scarcely any more differences than their succes 

 sors present at the present day, may be taken as 

 examples. With this must be connected the further 

 fact that nearly all the early types of life seem very 

 long ago to have reached stages so definite and fixed 

 that they became apparently incapable of further 

 development, constituting what have recently been 

 called terminal forms. ] 



A further difficulty arises from our failure to find 

 satisfactory examples of the almost infinite alleged 

 connecting links which must have occurred in a 

 gradual development. This, it may be said, proceeds 

 from the imperfection of the record ; but when we 

 find abundance of examples of the young and old of 

 many fossil species, and can trace them through their 

 ordinary embryonic development, why should we not 

 find examples of the links which bound the species 

 together ? An additional difficulty is caused by the 

 fact that in most types we find a great number of 

 kinds in their earlier geological history, and that they 

 dwindle rather than increase as they go onward. This 

 fact, established in so many cases as to constitute an 

 actual law of palaeontology, is altogether independent 

 of the alleged imperfection of the record. 



Objections of this kind appear to be fatal to the 



1 Clelland, Journal of Anatomy and Physiology. 



C 



