FAMILY CHARACTERISTICS. 123 



in some green rookery of the Old World, or the 

 Crow of our woods, with its long, melancholy 

 caw that seems to make the silence and solitude 

 deeper ? Compare all the sweet warblers of the 

 Songster Family, the Nightingales, the Thrush- 

 es, the Mocking-Birds, the Robins ; they differ in 

 the greater or less perfection of their note, but 

 the same kind of voice runs through the whole 

 group. 



These affinities of the vocal systems among 

 animals form a subject well worthy of the deep- 

 est study, not only as another character by which to 

 classify the Animal Kingdom correctly, but as bear- 

 ing indirectly also on the question of the origin of 

 animals. Can we suppose that characteristics like 

 these have been communicated from one animal 

 to another ? When we find that all the members 

 of one zoological Family, however widely scat- 

 tered over the surface of the earth, inhabiting 

 different continents and even different hemi- 

 spheres, speak with one voice, must we not believe 

 that they have originated in the places where 

 they now occur with all their distinctive pecu- 

 liarities ? Who taught the American Thrush to 

 sing like his European relative ? He surely did 

 not learn it from his cousin over the waters. 

 Those who would have us believe that all ani- 

 mals have originated from common centres and 

 single pairs, and have been thence distributed 



