BOOK III 



EVOLUTIONARY IDEAS IN PALEONTOLOGY 



FKOM the date of the appearance of the works 

 of Haeckel that is to say, from about the 

 year 1870 the publication of zoological studies 

 founded on transformist theory became so abun- 

 dant that it would be difficult for us to follow, 

 even at a distance, the progress and development 

 of the evolutionist doctrine in the various fields 

 of embryology, comparative anatomy, morphology, 

 and the classification of the living animal kingdom. 

 Before this overflowing invasion of facts and 

 theories, we shall be compelled to abandon almost 

 entirely the zoological side of the question and to 

 restrict ourselves to the study of fossil animals and 

 to the examination, in the light of the descent 

 hypothesis, of the most important works to which 

 these beings have given rise. We shall leave on 

 one side works of detail and only consider works 

 of generalization in which we can more easily 

 follow the dawn of leading ideas and the exposition 

 of principles in the matter of philosophical palaeon- 

 tology. 



