362 



BIOLOGY AND ITS MAKERS 



velop they become successively more and more compleXj 

 and in their shifting history many rudimentary organs arise 





. --^y^-y ^k:":[i:«il'iii:(ii!i ill ii ii. ':i:";ii 



ii|i;l!i!!|iii:«SU^: ii^^li- 



Mi 



I'll .'i,:'.^^- 



Fig. 108. — Fossil Remains of a Primitive Bird (Archeopteryx). 

 From the specimen in the BerHn Museum. (After Kayser.) 



and disappear. For illustration, in the young chick, devel- 

 oping within the hen's egg, there appear, after three or four 



