280 TOWARDS THE HUMAN FORM 



consisting simply in the hatching of ordinary eggs inside the 

 oviducts, and depending often on more or less temporary 

 external conditions — was more widespread among Reptiles in 

 the past than it is to-day. It is true that we have not up to the 

 present discovered fossilized eggs of these large animals which, 

 however, like Crocodiles' eggs, must have been protected by 

 a very strong shell. Be this as it may, the young, like the 

 eggs, were equally exposed to the teeth of Mammals small 

 enough and alert enough to escape all pursuit with ease, or 

 to the beaks of Birds whose wings would carry them out of 

 danger by capture. 



With regard to cerebral development, Mammals and Birds 

 were already gifted in a very different degree from the colossal 

 brutes of the reptilian class. They were clever enough to save 

 themselves in time from the least menace on the part of these 

 creatures. Just as their nervous system, taken as a whole, 

 has given to Vertebrates supremac}' over the other animals, 

 so the improvement in the brain was to give the warm-blooded 

 Vertebrates supremacy over the Vertebrates whose blood 

 had a variable temperature. With Tertiary times, intelligence, 

 which had already built up instinct in insects, though it has 

 subsequently become frozen in their tiny brains, was to re- 

 appear on the scene and gradually expand till, by its possession, 

 Man should become master of the world. 



