. The structure and life of birds . Fig. 11.—Part of vertical column of , Epiphyses, applied to anterior and posterior end of centrum of each vertebra. developed in the Duck-billed Platypus, the lowest ofmammals, with a decidedly reptilian anatomy. D 34 THE STRUCTURE AND LIFE OF BIRDS PCO (5) Birds have a single coracoid ; in reptiles it isdivided into two, the coracoid proper and in the Rhea we find a very conspicuous, thoughrudimentary, survival of the latter, and in the Ostrichthe bone is complete. (6) The birds feathercorresponds to the hornycoating of the re
. The structure and life of birds . Fig. 11.—Part of vertical column of , Epiphyses, applied to anterior and posterior end of centrum of each vertebra. developed in the Duck-billed Platypus, the lowest ofmammals, with a decidedly reptilian anatomy. D 34 THE STRUCTURE AND LIFE OF BIRDS PCO (5) Birds have a single coracoid ; in reptiles it isdivided into two, the coracoid proper and in the Rhea we find a very conspicuous, thoughrudimentary, survival of the latter, and in the Ostrichthe bone is complete. (6) The birds feathercorresponds to the hornycoating of the reptilesscale. The snake moults,when, as we say, he sheds his skin. In 1861 there wasfound in the LithographicStone at Solenhofen inBavaria the form of ananimal very different fromany that had ever beenseen either alive or asfossils. This stone be-longs to the Jurassic sys-tem and, consequently,was deposited in theSecondary or Mesozoicperiod, and long, too,before that period wasconcluded. Here was afeathered creature pre-served in the form of abas-relief, with the detail standing out so distinct andclear, that something even of the minute structure ofthe feathers might be seen. As Sir Richard Owenshowed, it was a bird of a very primitive form. The CO % Fig. -Coracoid of Rhea. coracoid ; pco, p
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