the bony structure of the hand remains the same in the Ostrich and in the American Rhea; in the Cassowary, however, and the Apteryx of New Zealand, the fingers are reduced to one. The last stage in the atrophy of the organ of flight is seen in the giant and extinct birds of New Zealand, the Moa or Dinornis, in which no trace of a wing has been so far discovered. But in some of these birds in which the wing is reduced in size, or so simplified in structure that it can no longer serve its legitimate purpose, it is made use of for other purposes. When the Ostrich skims along the surface of the sandy deserts where it is often found, it holds out both wings, which are compared to sails; they possibly serve rather as the pole of the tight-rope walker, to preserve the balance of the bird when hurrying along at full speed. In the Secretary Vulture of Africa the wings can be used for flying, but they are also used as weapons wherewith to combat the poisonous snakes upon which the bird so usefully feeds. It strikes down the venomous serpent when the latter is attempting to strike the bird. The Chauna of South America has strong spurs upon its wings, which are used for fighting as well as for flying. But the most curious use to which wings are put is afforded by the Penguin. If the reader has never seen the ‘diving birds’ fed at the Zoological Gardens, let him go there on the first opportunity, and see how rapidly and gracefully the Penguin ‘flies’ under water by the flapping of its wings. They are shorter than those of most birds, and the feathers have become flattened and almost scale-like, so as to offer no resistance to the water; at the same time the bones of the wing are flattened, so that a broad surface is provided, which of course acts like an oar. With this oar-like wing the Penguin can outswim a small fish. Sternum and Ribs.