The Reign of Reptiles 



greatest amount of strength is combined with 

 the use of the least amount of material, for 

 they are made of many comparatively thin 

 plates so put together as to be braced in every 

 direction. So, instead of being massive, clumsy 



A vertebra of Brontosaurus. 



bones, they are, considering their bulk, light, 

 while in many instances they were further 

 lightened by being hollowed out at the sides. 

 This is noted in the name of Barosawnis, air 

 lizard, applied by Professor Marsh to one 



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