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 zodlogical Family, however widely scat- 
tered over the surface of the éarth, 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 
