. Biology in America. Biology. The Story of the Rocks ii^ Apteryx, or the kiwi of New Zealand, a country which in its fauna is a sort of old curiosity shop, retaining such relics of the past as the Port Jackson sliark, the tuatara, the kiwi and until recently the moas. Yet a further legacy from his reptilian ancestry did Archaiopteryx possess. This is a set of abdominal ribs, or rib-like bones in the ventral wall of the abdomen, which he shared in common with the New Zealand lizard and the crocodile. As to how birds took to flying we of course have no certain knowledge. But we have some very i
. Biology in America. Biology. The Story of the Rocks ii^ Apteryx, or the kiwi of New Zealand, a country which in its fauna is a sort of old curiosity shop, retaining such relics of the past as the Port Jackson sliark, the tuatara, the kiwi and until recently the moas. Yet a further legacy from his reptilian ancestry did Archaiopteryx possess. This is a set of abdominal ribs, or rib-like bones in the ventral wall of the abdomen, which he shared in common with the New Zealand lizard and the crocodile. As to how birds took to flying we of course have no certain knowledge. But we have some very ingenious and interesting theories. In the first place what was the probable origin of the feathers? A feather consists of a central shaft or quill from which extend two rows of branches or barbs, and these. Part of a Feather Showing shaft, barbs, barlniles and liooks. Original. in turn give rise to a series of little barbs or barbules which interlock with one another by means of rows of small hooks; the whole forming a firm resistant membrane serving as a propeller in the case of the wing feather, a rudder in that of the tail feathers, and a protective and insulating covering for the general body surface. At the base of the quill is a small papilla or projection of the dermis, or lower layer of the skin, which carries nerves and blood vessels and serves to nourish the growing feather. The feather itself arises as a tube of modified horny cells derived from the epidermis, or outer skin layer, whicli splits into several parts in develop- ment, which spread out to form the barbs and barbules. This. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Young, R. T. (Robert Thompson), b. 1874. Boston, R. G. Badger
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