Mr. Swainson remarks:--"The apparent disproportion of the bill is one of the innumerable instances of that beautiful adaptation of structure to use which the book of nature everywhere reveals. The food of these birds consists principally of the eggs and young of others, to discover which nature has given them the most exquisite powers of smell." Again, the nests in which the Toucan finds its food are often very deep and dark, and its bill, covered with branches of nerves, enables the bird to feel its way as accurately as the finest and most delicate finger could. From its feeding on eggs found in other birds' nests, it has been called the Egg-sucker. Probably there is no bird which secures her young offspring better from the monkeys, which are very noisome to the young of most birds. For when she perceives the approach of these enemies she so settles herself in her nest as to put her bill out at the hole, and give the monkeys such a welcome therewith that they presently break away, and are glad to escape. Professor Owen, in his minute examination of the mandibles, remarks that the principle of the cylinder is introduced into the elaborate structure; the smallest of the supporting pillars of the mandibles are seen to be hollow or tubular when examined with the microscope. Light and almost diaphonous as is the bill of the Toucan, its strength and the power of the muscles, which act upon the mandibles, are evident in the wrenching and masticatory processes. When taking fruit, the Toucan generally holds it for a short time at the extremity of his bill, applying to it, with apparent delight, the pointed tip of the slender tongue: the bird then throws it, with a sudden upward jerk, to the throat, where it is caught and instantly swallowed. Mr. Gould divides the Toucans into six genera. 1. The true Toucans, with large and gaily-coloured bills, plumage black. 2. The Araçaris, with smaller beaks, plumage green, yellow, and red. 3. The Banded Aracauris, an Amazonian genus, proposed by Prince C. L. Bonaparte. 4. Toucanets, small, with crescent of yellow on the back, and brilliant orange and yellow ear-coverts. 5. Hill Toucans of the Andes. 6. Groove-bills, grass-green plumage. A very fine true Toucan, figured by Mr. Gould, is remarkable for the splendour and size of the bill, of a fine orange-red, with a large black patch on each side. Powder-flasks are made of large and finely-coloured bills. The naked skin round the eye is bright orange. The chest is white, with a tinge of sulphur below, and a slight scarlet margin. Upper tail-coverts, white; under tail-coverts, scarlet; the rest of the plumage, black. Several specimens of this beautiful bird lived both in the menagerie of the late Earl of Derby, at Knowsley, and in the gardens of the Zoological Society. It is a native of Cayenne, Paraguay, &c.