There is a chapter in the Natural History of Animals that has hardly been touched upon as yet, and that will be especially interesting with reference to Families.  The voices of animals have a family character not to be mistaken.  All the Canidae bark and howl:  the Fox, the Wolf, the Dog have the same kind of utterance, though on a somewhat different pitch.  All the Bears growl, from the White Bear of the Arctic snows to the small Black Bear of the Andes.  All the Cats miau, from our quiet fireside companion to the Lions and Tigers and Panthers of the forest and jungle.  This last may seem a strange assertion; but to any one who has listened critically to their sounds and analyzed their voices, the roar of the Lion is but a gigantic miau, bearing about the same proportion to that of a Cat as its stately and majestic form does to the smaller, softer, more peaceful aspect of the Cat.  Yet, notwithstanding the difference in their size, who can look at the Lion, whether in his more sleepy mood as he lies curled up in the corner of his cage, or in his fiercer moments of hunger or of rage, without being reminded of a Cat?  And this is not merely the resemblance of one carnivorous animal to another; for no one was ever reminded of a Dog or Wolf by a Lion.  Again, all the Horses and Donkeys neigh; for the bray of the Donkey is only a harsher neigh, pitched on a different key, it is true, but a sound of the same character,—­as the Donkey himself is but a clumsy and dwarfish Horse.  All the Cows low, from the Buffalo roaming the prairie, the Musk-Ox of the Arctic ice-fields, or the Jack of Asia, to the Cattle feeding in our pastures.  Among the Birds, this similarity of voice in Families is still more marked.  We need only recall the harsh and noisy Parrots, so similar in their peculiar utterance.  Or take as an example the web-footed Family,—­do not all the Geese and the innumerable host of Ducks quack?  Does not every member of the Crow Family caw, whether it be the Jackdaw, the Jay, the Magpie, the Rook 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 Thrushes, 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 deepest study, not only as another character by which to classify the Animal Kingdom correctly, but as bearing 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 scattered over the surface of the earth, inhabiting different continents and even different hemispheres, speak with one voice, must we not believe that they have originated in the