V. On the Mechanical Appliances by which Flight is attained in the Animal Kingdom.

In this we have an explanation of the curiously modified hand of the Bat,-of the webbed hands and feet of the Otter, Ornithorhynchus, Seal, and Walrus,-of the expanded tail of the Whale, Porpoise, Dugong, and Manatee,-of the feet of the Ostrich, Apteryx, and Dodo, exclusively designed for running,-of the feet of the Ducks, Gulls, and Petrels, specially adapted for swimming,-and of the wings and feet of the Penguins, Auks, and Guillemots, especially designed for diving.Other a,nd intermediate modific2tions occur in the Flyingfish, Flying Lizard, and Flying Squirrel ; and some animals, as the Frog, Newt, and several of the aquatic insects (the Ephemera or May-fly for example *), which begin their career by swimming, come ultimately t o walk, leap, and even fly+.Every degree and variety of motion, therefore, which is peculiar to the land,-and to the sea and air-navigating animals as such, is imitated by others which take to the elements in question secondarily or at intervals.As the space at my disposal will not admit of my going into the several arrangements by which locomotion is attained in the animal kingdom as a whole, I will allude only to such as illustrate in a progressive manner the several kinds of motion on the land and in or on the water, reserving for the third and concluding part of the paper the subject of flight as exemplified in the insect, bat, and bird.The following, among other animals, have been referred to, and their movements, whether on land, on or in the water, or air, for the most part described and figured.They may be hastily classified as follows