BIRD GENEALOGY 



herons elevate the bastard wing at times as 

 they climb about the trees, but I have never 

 seen them attempt to use it for grasping. 



A study of the youthful stages in the life 

 of any creature, therefore, often throws light 

 on its family connections. If we go back far- 

 ther still, more light is thrown, for the em- 

 bryonic stages of every animal present in 

 epitome — with many gaps, it is true — the 

 life of its ancestors. What could be more 

 significant of a reptilian ancestry than the 

 claws which in the embryo of the penguin, 

 for example, are found on each finger of the 

 wings. In adult birds these claws, though 

 generally lacking, still persist to a certain 

 extent in some. Thus many ducks are pro- 

 vided with claws on the index and thumb of 

 each wing, an evident survival of a part once 

 important in the ancestry of the race. In 

 the same way the hind limbs and the skull of 

 birds show evidences of reptilian ancestry. 

 The most striking feature, the teeth, present 

 in the archaeopteryx and later fossil birds, is 

 now entirely eliminated, although traces of 

 teeth are said to be present in embryo parrots. 

 Archaeopteryx possessed a very reptilian tail 

 made up of seven vertebrae, each bearing a 



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