134 ESSAY ON CLASSIFICATION. Part I. 



18th. The limitation of the range of changes which animals undergo during their 

 growth, exhibits thought; it shows most strikingly the independence of these changes 

 of external influences, and the necessity that they should be determined by a 

 power superior to these influences. 



19th. The unequal limitation in the average duration of the life of individuals 

 in different species of animals, exhibits thought; for, however uniform or however 

 diversified the conditions of existence may be under which animals live together, 

 the average duration of hfe, in different species, is unequally hmited. It points, there- 

 fore, at a knowledge of time and space, and of the value of time, since the phases 

 of life of different animals are apportioned according to the part they have to per- 

 form upon the stage of the woi'ld. 



20th. The return to a definite norm of animals which multiply in various ways, 

 exhibits thought. It shows how wide a cycle of modulations may be included in 

 the same conception, without yet departing from a norm expressed more directly in 

 other combinations. 



21st. The order of succession of the different types of animals and plants charac- 

 teristic of the different geological epochs, exhibits thought. It shows, that while 

 the material world is identical in itself in all ages, ever different types of organized 

 beings are called into existence in successive periods. 



22d. The localization of some types of animals upon the same points of the sur- 

 face of the globe, during several successive geological periods, exhibits thought, 

 consecutive thought ; the operations of a mind acting in conformity with a plan 

 laid out beforehand and sustained for a long period. 



23d. The limitation of closely allied species to different geological periods, exhibits 

 thought; it exhibits the power of sustaining nice distinctions, notwithstanding the 

 interposition of great disturbances by physical revolutions. 



24th. The parallelism between the order of succession of animals and plants 

 in geological times, and the gradation among their living representatives, exhibit 

 thought ; consecutive thought, superintending the whole development of nature from 

 beginning to- end, and disclosing throughout a gradual progress, ending with the 

 introduction of man at the head of the animal creation. 



25th. The parallelism between the order of succession of animals in geological 

 times and the changes their living representatives undergo during their embryological 

 growth, exhibits thought; the- repetition of the same train of thoughts in the phases 

 of growth of living animals and the successive appearance of their representatives 

 in past ages. 



26th. The combination, in many extinct types, of characters which, in later ages, 

 appear disconnected in different types, exhibits thought, prophetic thought, foresight; 

 combinations of thought preceding their manifestation in Mving forms. 



