2. _Insessores_, or perching birds. These birds have all feet formed for perching, the hind toe springing from the same place as the other toes, which gives them great power of grasping. Their legs are of moderate length, and their claws not sharply curved. This order includes the thrushes, nightingales, and all the finest songsters of our groves, with the robin-redbreast, the sparrow, and other birds seen about dwellings, the swallows, the larks, the crow family, the kingfishers, the birds of paradise, and the humming birds. 3. _Scansores_, or climbers. These birds have two toes before and two behind. This construction gives them such great power of climbing, that they can ascend the perpendicular trunk of a tree. The principal birds in this order are the parrots, the cuckoos, and the woodpeckers. 4. _Rasores_, or gallinaceous birds. These birds have the head small in proportion to the body. The bill is generally short, with the upper mandible somewhat curved. The nostrils have usually a protecting fleshy membrane. The tarsus, or lower part of the leg, is long and bare, and there are four toes, those in front being united by a slight membrane, while that behind is generally higher up the leg, and smaller than the others. This order comprises most of the birds used as food, and includes the peacock, the turkey, the common cock and hen, the partridge, the pheasant, and the pigeon family. 5. _Grallatores_, or Waders. These birds are characterised by their long and slender legs, and by the thighs being more or less bare. There are three anterior toes, more or less united at the base by a membrane, or rudimentary web. The hind toe is wanting in some members of the order. This order contains the ostrich family, the bustards and plovers; the cranes, herons, and storks; and the snipes and woodcocks. 6. _Palmipedes_, or web-footed birds. These birds have the legs and feet short, and placed behind, with their fore toes united by a thick and strong membrane. The neck is much longer than the legs, and their bodies are covered with a dense layer of down beneath the outer plumage, which is close, and imbued with an oily fluid that repels the water. The principal birds in this order are the grebes, the auks and penguins, the petrels, the pelican and cormorant and the swans, ducks, and geese. By many ornithologists the pigeons and ostriches are considered to form distinct orders, called respectively _Columbæ_ and _Cursores_. THE REPTILIA,