. In the bat, the wing surface is a membrane, but it is supported by several elongated fingers Drawings by John C. Germann nonetheless successful, for it continued over a period of some 50 to 60 millions of years. But it wasn't so successful a pattern for flight as was that of the birds, or of the bats. The Birds Birds are little more than "glorified rep- ; True enough, to the average spectator there seems to be nothing in common be- tween the gorgeous blue and white flash of the jay, screaming his indignation through the high branches of the oak tree, and the silent and sinuou
. In the bat, the wing surface is a membrane, but it is supported by several elongated fingers Drawings by John C. Germann nonetheless successful, for it continued over a period of some 50 to 60 millions of years. But it wasn't so successful a pattern for flight as was that of the birds, or of the bats. The Birds Birds are little more than "glorified rep- ; True enough, to the average spectator there seems to be nothing in common be- tween the gorgeous blue and white flash of the jay, screaming his indignation through the high branches of the oak tree, and the silent and sinuous menace of the blacksnake gliding through the grass, the object of the bird's imprecations. But under- neath the feathers of the bird and the shin- ing scales of the reptile the resemblances are there, and when the ancestries of these two apparently so dissimilar vertebrates are traced back through the fossil record the resemblances become all the more signifi- cant—the bird becomes ever more reptilian, so that there can be little doubt as to its earliest orgin. The birds, although classified as a separate class of the vertebrates, are essen- tially of basic thecodont ancestry. They are lightly built, with strong, hollow bones. Not only are the bones extraordinarily pneumatic, for the sake of lightness, but also there are a number of air sacs in the body of the bird, which further contributes to its flying ability. The skull shows an un- usual amount of fusion of the bones (just as was the case in the pterosaurs). The back is short and strong, while the neck is rather long. The pectoral and pelvic girdles are very strong; the latter is firmly attached to the spinal column by a greatly lengthened and strengthened series of articulations be- tween the vertebrae and the sacral portion of the pelvis. In the typical flying birds the 100
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Keywords: ., bookcentury1900, bookpublishernewyork, booksubjectreptilesfossil
