NO PROGRESSIVE ORGANISATION. 



a gradually increasing degree of organic perfection from one 

 geological period to another, from the first appearance of animal 

 life upon the globe to the human period. 



The only facts which have given colour to this supposition, are 

 the lateness of the period at which the Yertehrated animals of 

 the highest order of organisation, Mammifers and Birds, appeared 

 in any considerable numbers upon the globe, and more especially 

 the fact, that the human race did not appear until after the close 

 of the Tertiary age. 



5133. That the conclusion thus deduced is a premature gene- 

 ralisation, will appear from an examination of the classes and 

 genera which have prevailed, during all the successive ages from 

 the Palaeozoic to the human. 



If the supposition of progressive improvement in organisation 

 were well founded, it must naturally be expected that in the 

 earliest period of the Palaeozoic, the lowest orders only of organi- 

 sation would appear, and that consequently the Radiata alone 

 would be found there, while on ascending through the succeeding 

 periods of the Triassic, Jurassic, Cretaceous, and Tertiary ages we 

 should find gradually appearing the more perfect orders of Mol- 

 lusca, Annulata, and Vertebrata. On the contrary, it appears, 

 from what has been stated, that in the Palaeozoic age animals of 

 all the orders from the lowest to the highest were created in a 

 proportion not very different from that in which they now exist. 



534. It will be interesting, however, to consider the characteris- 

 tics of the organisation of the genera composing each of the orders 

 existing at each successive period ; for although no progressive 

 increase of perfection might be manifested with regard to the 

 orders, such progression might nevertheless appear in the yensra 

 of these orders created from period to period. 



535. A due examination, however, of the genera of the several 

 orders existing at each period will show that no such pro- 

 gressive increase of perfection in the organisation has been 

 manifested. 



536. Of the Radiata eight orders were called into being in the 

 Palaeozoic age, and none of superior organisation in the succeed- 

 ing ages. Indeed a rigorous examination of the succession of 

 fauna of this division leads to the contrary conclusion, showing that 

 the most perfect prevailed in greatest numbers at the earliest ages. 



A similar examination of the division of Mollusca gives a like 

 result, no gradually increasing perfection of organisation being 

 discoverable. 



537. In like manner the supposition of progressively improved 

 organisation from age to age would lead us to expect in Annu- 

 lated animals all the orders of the less perfect organisation in the 



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