EARLIEST TYPES OF ANIMALS. 31 



our globe in the same manner, by a succession of ever 

 renewed and short-lived individuals. 



As, however, the second chapter of this work is entirely 

 devoted to the consideration of the different kinds and 

 the different degrees of affinity existing among animals, I 

 will not enter here into any details upon this subject, but 

 simply recall the fact, that, in the course of time, investi- 

 gators have agreed more and more with one another in 

 their estimates of these relations, and built up systems 

 more and more conformable to one another. Tin's result, 

 which is fully exemplified by the history of our science, 1 

 is in itself sufficient to show that there is a system in 

 nature, to which the different systems of authors are suc- 

 cessive approximations, more and more closely agreeing 

 with it, in proportion as the human mind has understood 

 nature better. This growing coincidence between our 

 systems and that of nature shows, further, the identity of 

 the operations of the human and the Divine intellect ; 

 especially when it is remembered to what an extraor- 

 dinary degree many d priori conceptions, relating to 

 nature, have in the end been proved to agree with the 

 reality, in spite of every objection at first offered to them 

 by empiric observers. 



SECTION VII. 



SIMULTANEOUS EXISTENCE IN THE EARLIEST GEOLOGICAL 

 PERIODS, OF ALL THE GREAT TYPES OF ANIMALS. 



It was formerly believed by geologists and palaeontolo- 

 gists that the lowest animals first made their appearance 



1 SPIX (J.), Geschichte und Beur- DB BLAINVILLE (H.), Histoire des 



theilung aller Systeme in der Zoolo- sciences de 1'organisation et de leurs 



gie ; Niirnberg, 1811, 1 vol. Svo. progres; Paris, 1847, 3 vols. 8vo. 



CUVIER (G.), Histoire des progres des POTJCHET (F. A.), Histoire des sci- 



sciences naturelles; Paris, 1826, 4 ences naturelles au moyen age ; Pa- 



vols. Svo. Histoire des sciences na- ris, 1853, 1 vol. Svo. Compare, also, 



turelles, etc.; Paris, 1841,5 vols. Svo. Chap. II below. 



