. The structure and life of birds . xisting birds a claw is foundon No. I, in a fair number on No. 2 as well, in theyoung Ostrich on all three. The third digit has notbeen reduced to a single phalanx. But this is no greatbarrier. In birds of our own day the final phalanxis often lost on digit I. (2) The length and strengthof the humerus and forearm remind one much ofexisting birds. (3) The acetabulum or socket of thethigh joint, seems to have been closed only withmembrane. (4) Scales, not feathers, are found on allknown lizards. There are some interesting points which, if rep-tilian, are also
. The structure and life of birds . xisting birds a claw is foundon No. I, in a fair number on No. 2 as well, in theyoung Ostrich on all three. The third digit has notbeen reduced to a single phalanx. But this is no greatbarrier. In birds of our own day the final phalanxis often lost on digit I. (2) The length and strengthof the humerus and forearm remind one much ofexisting birds. (3) The acetabulum or socket of thethigh joint, seems to have been closed only withmembrane. (4) Scales, not feathers, are found on allknown lizards. There are some interesting points which, if rep-tilian, are also avian. The vertebrae seem to have 1 Dr. Hurst (Natural Science, October, 1893) has boldly triedto show that archaeopteryx had really more than three fingers,and that one or two with larger stronger bones have left noimpression on the stone. But when even the delicate forms ofthe feathers are preserved, it is wonderful that there should beno trace of these bones either in the Berlin Archaeopteryx, or inthe one at the British 38 THE STRUCTURE AND LIFE OF BIRDS chap. been bi-concave, , the centra presented hollowsat either end. This is a form of vertebra foundin very primitive reptiles, , in the Hatteria is also found in Ichthyornis, afossil bird of more recent date thanArchaeopteryx. And what is far morestrange, the Gull, a highly special-ised, a thoroughly modernised bird,has some of its dorsal vertebrae con-cave behind, thus conforming to anold reptilian type, and one almostfig. 16.—Vertebra of bi-concave, which thus carries us back Hatteria Lizard. .1 r ,mi •,• . to reptiles oi a still more primitive C, centrum ; it is am- L L phicoeious, con- In teeth, as I hope to show cave at each end. x presently, there is nothing unavian. It would be very interesting to know how thisbird lived. Of one thing we may be certain—hewas a poor flyer. With its three long unconnectedfingers the wing must have been a weak one. Prob-ably he fluttered,
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