1 6 EVOLUTION. 



man have slowly arisen through all the ranks of life 

 below him, each great division leaving its record in 

 the unfolding germ of the latest individual ? 



The embryos of all vertebrates, including man, 

 have tails, and all show the gill-clefts of fishes in their 

 early condition. Wilson says : "But reptiles, birds, 

 and quadrupeds are lung-breathers and possess gills 

 at no period of their life. Why should they develop 

 gill-clefts, which bear no relation to the wants of their 

 adult existence ? W^hy does this useless expenditure 

 of creative power exist ? " The only answer is that 

 the forms are inherited from early ancestors. Dar- 

 win says : •* We have only to suppose that a former 

 progenitor possessed the parts in question in a per- 

 fect state, and that under changed habits of life they 

 became greatly reduced, either from simple disuse or 

 through the natural selection of those individuals 

 that were least encumbered with a superfluous 

 part." 



Metamorphosis, 



It is not only in the ^gg or embryo that we see 

 these developments. Many animals after birth 

 change to higher forms. The frog appears first as a 

 fish, then as a tailed newt, and finally as the tailless 

 air-breathing frog. The development of the butter- 

 fly from the caterpillar is a familiar instance. The 

 starfish is first a swimming worm-like creature. The 

 flat sole begins life at the top of the water, with a 



