230 EXTINCT MONSTERS 
the above Museum, with the skeleton of a modern ostrich, among 
the fossil birds. The Fayum of Egypt (see p. 262) has also yielded 
a portion of a limb-bone of some large struthious bird. 
It will thus be seen that big struthious birds have a long 
history, going far back into the Tertiary era, and that they once 
had a much wider geographical range than they have now. 
Doubtless, future discoveries will tend to fill up the gaps between 
all these various types, both living and extinct, and to connect 
them together in one chain of evolution. Possibly the bird 
evolved from an arboreal reptile. 
