. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. AVKS. 351 In the Ostrich the feathers have no accessory plume : in the Rhea it is represented by a tuft of down; in the Emeu, on the contrary, the accessory plume equals the original feather, so that the quill supports two shafts ; and in the Cassowary, besides the double feather, there is also a second accessory plume, so that the quill supports three distinct shafts and vanes. The feathers vary in form in different parts of the bird according to their functions, and afford zoological characters for the distinction of s
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. AVKS. 351 In the Ostrich the feathers have no accessory plume : in the Rhea it is represented by a tuft of down; in the Emeu, on the contrary, the accessory plume equals the original feather, so that the quill supports two shafts ; and in the Cassowary, besides the double feather, there is also a second accessory plume, so that the quill supports three distinct shafts and vanes. The feathers vary in form in different parts of the bird according to their functions, and afford zoological characters for the distinction of species; they have, therefore, received in Ornithology distinct names. Those which surround or cover the external opening of the ear are termed ' auriculars.' Those which lie above the scapula and humerus are called the ' scapulars.' The small feathers which lie in several rows upon the bones of the antibrachium are called the ' lesser coverts' (tectrices primte). Those which line the under or inner side of the wings are the ' under coverts.' The feathers which lie immediately over the quill-feathers are the ' greater coverts' (tectrices secunda). The largest quill-feathers of the wing, which arise from the bones of the hand, are termed ' primaries' (primores). Those which rise from the ulna, towards its distal end, are the ' secondaries' (secondaries). Those which are attached to its proximal ex- tremity are the ' tertiaries' (tertiarite). These in some birds, as the Woodcock and Snipe, are so long as to give them the appearance, when flying, of having four wings. The quill-feathers which grow from the phalanx, representing the thumb, form what is termed the bastard wing (alula spuria). In considering the structures which deter- mine the powers of flight in different birds, it is necessary to take into account the structure, forms, and proportions of the wing-feathers, as well as the development of the bones and muscles which support and move them; as much depends upon the mec
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