. Animal flight; a record of observation . ipsof these feathers are bent downwards producing theappearance of the dip movement. From the dorsalaspect of the wing two muscles may be seen that havethe power of rotating the front edge of the wing-tipin the opposite direction. These muscles come intoaction at the end of a dip movement to return thewing-tip to its original 1 Rotation in such a direction that the front edge of the wing-tip goes down, and the hinder•edge up, may be described as rotation downwards. Rotation of the wing-tip in the oppositedirection may be described as rotati
. Animal flight; a record of observation . ipsof these feathers are bent downwards producing theappearance of the dip movement. From the dorsalaspect of the wing two muscles may be seen that havethe power of rotating the front edge of the wing-tipin the opposite direction. These muscles come intoaction at the end of a dip movement to return thewing-tip to its original 1 Rotation in such a direction that the front edge of the wing-tip goes down, and the hinder•edge up, may be described as rotation downwards. Rotation of the wing-tip in the oppositedirection may be described as rotation upwards. F 7o ANIMAL FLIGHT. I have also found these muscles in the wings ofthe common vulture, the Adjutant (Leptoptilus dubius)ythe Sarus (Grus antigone), and other birds. Fig. 14 represents diagrammatically the structureof the wing-tip : A B is the axis of the wing: I. to the large wing-tip feathers, usually known as theprimary quills. Of these, I. to IV. are attached to thephalangeal bones C, forming therewith a practically. Fig. 14. Structure of wing-tip of vulture. A B.—Axis of K L.—Digital quill mass, consisting of first four primary quills,I., II., III., IV., which form an almost solid mass with the phalangealbone mass C. The digital quill mass is articulated at H to thepoint F of the metacarpal quill mass M D. This latter consists of thefused metacarpal bones D, to which are firmly attached the remain-ing primary quills V., VI., VII., VIII., IX., and X. These quillsmay conveniently be termed metacarpal quills. The metacarpal quillmass is articulated at E, the carpal joint, to the main part ofthe wing. For the sake of clearness, the alula or bastard wing has been omitted. solid mass. These first four quills may convenientlybe described as the digital quills. The remaining-primary quills V. to X. are similarly attached to themetacarpal bone D. These quills may therefore bedescribed as the metacarpal quills. The point ofattachment of the metacarpal q
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