



8 THE HISTORY OF CEEATIOK 



Four years ago I set up a number of hypothetical genea- 

 logies for the larger groups of organisms in the systematic 

 introduction to my General History of Development (Gen. 

 Morph. vol. ii.), and thereby, in fact, made the first attempt 

 actually to construct the pedigrees of organisms in the 

 manner required by the theory of development. I was 

 quite conscious of the extreme difiiculty of the task, and as 

 I undertook it in spite of aU discouraging obstacles, I claim 

 no more than the merit of having made the first attempt and 

 given a stimulus for other and better attempts. Probably 

 most zoologists and botanists were but little satisfied with 

 this beginning, and least so in reference to the special domain 

 in which each one is specially at work. However, it is cer- 

 tainly in this case much easier to blame than to produce 

 something better, and what best proves the immense diffi- 

 culty of this infinitely complicated task is the fact that no 

 naturalist has as yet supplied the place of my pedigrees by 

 better ones. But, like aU other scientific hypotheses which 

 serve to explain facts, my genealogical hypotheses may 

 claim to be taken into consideration until they are re- 

 placed by better ones. 



I hope that this replacement will very soon take place ; 

 and I wish for nothing more than that my first attempt 

 may induce very many naturalists to establish more accurate 

 pedigrees for the individual groups, at least in the special 

 domain of the animal and vegetable kingdom which 

 happens to be well known to one or other of them. By 

 numerous attempts of this kind our genealogical know- 

 ledge, ia the course of time, wiU slowly advance and 

 approach more and more towards perfection, although it can 

 with certainty be foreseen that we shall never arrive at a 



