The Secret Doctrine 2.8.29

Animals with bones, dragons of the deep, and flying Sarpas were added to the creeping things. They that creep on the ground got wings. They of the long necks in the water became the progenitors of the fowls of the air.

This is a point on which the teachings and modern biological speculation are in perfect accord. The missing links representing this transition process between reptile and bird are apparent to the veriest bigot, especially in the Ornithoscelidæ, Hesperornis, and the Archæopteryx of Vogt.