Although in the torrid zone we hardly ever meet with a single aboriginal species of plant or animal common to both hemispheres, yet the analogy of climate everywhere produces analogous organic forms, and when on surveying the feathered tribes of America, we are struck by any bird remarkable for its singularity of shape or mode of life, we may expect to find its representative in Asia, Africa, or Australia. [Illustration: RHINOCEROS HORNBILL.] Thus the enormous beak of the toucan is emulated or surpassed by that of the Indian Calao, or Rhinoceros Hornbill (_Buceros rhinoceros_) whose twelve-inch long, curved, and sharp-pointed bill, is, moreover, surmounted with an immense appendage in the form of a reverted horn, the use of which belongs as yet to the secrets of nature. While the toucans are distinguished by a gaudy plumage, the Calaos are almost entirely decked with a robe black as that of the raven, and enhancing the beautiful red and orange colours of their colossal beak. Generally congregating in small troops, like the toucans, they inhabit the dense forests, where they chiefly live on fruits, seeds, and insects, which they also swallow whole, throwing them up into the air and catching them as they fall. The clapping together of their mandibles causes a loud and peculiar noise, which towards evening interrupts the silence of the forest. The flight of a bird burdened with such a load must naturally be short: they hop upon their thick clumsy feet, and generally roost upon the highest trees. Like the toucans, the Indian Hornbills make their nest in the hole of some decaying tree, sometimes plastering up the entrance with mud, so as to leave but a small aperture, a practice which the Korwê, a species of African Hornbill, seems invariably to follow. The female having entered her breeding-place, in one of the natural cavities of the mopane tree, a species of Bauhinia, the male plasters up the entrance, leaving only a narrow slit by which to feed his mate, and which exactly suits the form of his beak. The female makes a nest of her own feathers, lays her eggs, hatches them, and remains with the young till they are fully fledged. During all this time which is stated to be two or three months, the male continues to feed her and the young family. The prisoner generally becomes quite fat, and is esteemed a very dainty morsel by the natives, while the poor slave of a husband gets so lean and weak, that on the sudden lowering of the temperature, which sometimes happens after a fall of rain, he is benumbed, falls down, and dies.