ORGANIC E VOL UTION. 45 



I have no space to go into the evidence of 

 similar " missing links " which have been recently 

 supplied by palaeontological researches in the case 

 of several other groups of animals ; but their 

 consideration seems to me quite to justify a 

 more recent utterance of Professor Huxley, who, 

 in 1878, wrote in the Encyclopedia Britannica : 

 " On the evidence of palaeontology, the evolution 

 of many existing forms of animal life from their 

 predecessors is no longer an hypothesis, but an 

 historical fact ; it is only the nature of the 

 physiological factors to which that evolution is 

 due which is still open to discussion." 



