Elementary text-book of zoology (1884) Elementary text-book of zoology elementarytextbo0201clau Year: 1884 THE 241 Jc tened to the thumb-joint (sometiino ivphn-rd by a spur) are called the bastard-wing (alula}. All the remiges are covered at their ba>e l>y shorter feathers, which are arranged in overlapping rows, and are known as coverts (tectrices, fig. 652, T}. In certain cases the wings may become so much reduced that the power of flight is almost or quite lost, a condition which is met with in some running and land birds (Dinornithidce, Kiwi and Ostrich), and also in cert
Elementary text-book of zoology (1884) Elementary text-book of zoology elementarytextbo0201clau Year: 1884 THE 241 Jc tened to the thumb-joint (sometiino ivphn-rd by a spur) are called the bastard-wing (alula}. All the remiges are covered at their ba>e l>y shorter feathers, which are arranged in overlapping rows, and are known as coverts (tectrices, fig. 652, T}. In certain cases the wings may become so much reduced that the power of flight is almost or quite lost, a condition which is met with in some running and land birds (Dinornithidce, Kiwi and Ostrich), and also in certain water (Penguin). The great contour-feathers of the tail are called rectrices (fit), because during flight they are used for altering the direction and for steering. There are, as a rule, twelve (sometimes ten or twenty and more) rec- trices attached to the last caudal vertebra in such a way that they can be moved singly, and unfolded laterally like a fan, as well as be all raised or depressed together. The roots of the tail quills are covered by a number of coverts, which in some cases attain an extra- ordinary size and shape, and constitute an ornament to the Bird (Peacock). When the power of flight is absent the tail loses its significance as a steering apparatus, and the tail quills are reduced or com- pletely absent. In such cases, however, some of the coverts may attain a considerable size as ornamental feathers. The hind limbs, which are principally used in the locomotion of the animal on firm ground present numerous varieties, according to the mode of locomotion of the Bird. In the first place, walking legs, or pries gradarii, and wading legs, or pedes vadantes, are to be distinguished (fig. 653). The former are much more completely leathered, being covered at least as far as the articulation of the heel: but they vary considerably. The following varieties may be distinguished (fig. 653) :—prfr* «.<H«<,,tantefi, with four toes directed VOL. II. 16 FIG. 6
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