88 ESSAY ON CLASSIFICATION. 



interesting would be a comparative study of the mode of 

 life of closely allied species ! how instructive a picture 

 might be drawn of the resemblance there is in this re- 

 spect between species of the same genus and of the same 

 family ! The more I learn upon this subject, the more am 

 I struck with the similarity in the very movements, the 

 general habits, and even in the intonation of the voices of 

 animals belonging to the same family ; that is to say, be- 

 tween animals agreeing in the main in form, size, struc- 

 ture, and mode of development. A minute study of these 

 habits, of these movements, and of the voice of animals, 

 cannot fail, therefore, to throw additional light upon their 

 natural affinities. 



AYhile I thus acknowledge the great importance of such 

 investigations with reference to the systematic arrange- 

 ment of animals, I cannot help regretting deeply that 

 they are not more highly valued with reference to the in- 

 formation they might secure respecting the animals them- 

 selves, independently of any system. How much is there 

 not left to study with respect to every species after it is 

 named and classified ! No one can read Nauman's Natural 

 History of German Birds without feeling that natural 

 history would be much further advanced, if the habits of 

 all other animals had been as accurately investigated and 

 as minutely recorded ; and yet that work contains hardly 

 anything of importance with reference to the systematic 

 arrangement of birds. We scarcely possess the most ele- 

 mentary information necessary to discuss upon a scien- 

 tific basis the question of the instincts, and in general the 

 faculties of animals, and to compare them together and 

 with those of man, 1 not only because so few animals have 



1 SCHEITLIN (P.), Versuch einer Stuttgart und Tubingen, 1 840, 2 vols. 

 vollstandigen Thierseelenkuude ; 8vo. CuviER(FRED.)Resume analyt- 



