Animals Before Mem 



all tlie bones of the skull is a very reptilian 

 character. One of the characteristics of modern 

 birds is, that the various bones of the cranium 

 unite at an early age, so that the cranium seems 

 made of one piece, while among reptiles they 

 remain free from one another throughout life. 

 This has a direct bearing on the fact that birds 

 soon reach their full size, while reptiles 23racti- 

 cally keejD on growing as long as they live. 



It may a^^pear surprising that the existence 

 of teeth in these Cretaceous birds, as well as 

 in the Archaeopteryx, was not recognized until 

 some time after their bones had been collected, 

 but it really is not. The presence of teeth is 

 such an un-bird-like character that no one looked 

 for them, while the teeth themselves are so 

 small as not to attract notice, the more that 

 they were so loosely implanted in the jaws 

 that they readily fell out after death. 



What does seem rather singular is that in 

 course of time teeth should have ceased to be 

 present in fish-eating birds, as such structures 

 would certainly be useful in holding wriggling, 

 slippery prey. It is all the stranger since some 



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