258 PROCEEDINGS OF THE ACADEMY OF [1895. 



and in many cases leave them largely to chance, their sole trust 

 being in concealment. 



The degree of care paid by existing reptiles to the fate of their 

 eggs, small as it is, may have been the result of a long-continued 

 struggle for existence. As the activity and ingenuity of their foes 

 increased, so may have increased reptilian care and fecundity. 

 Probably ages ago both less heed was given to the security of the 

 eggs than now and the peril was less imminent. There has very 

 likely been a campaign of education on both sides. Yet it may be 

 that the continued existence of the modern reptilian families is in a 

 measure due to some degree of care always exercised over their eggs. 

 And it is possible that little care may have been taken by the giant 

 Mesozoic reptiles, and that their extinction was largely due to this 

 cause. 



The views here expressed certainly lead us to a fuller compre- 

 hension of the situation in which the Cretaceous reptiles were placed. 

 These creatures, large and small alike, were egg layers, and their 

 eggs and young were exposed to the peculiar dangers above indi- 

 cated. To what extent they took care of their eggs we cannot know, 

 but to judge from the habits of existing reptiles their care was not 

 great. \Ve are aware that these huge creatures possessed very 

 small brains, and must conceive that they possessed little or no 

 intelligence, being governed in great measure by the instincts 

 acquired during past ages of slow development. These instincts 

 were gained at an early period in which the eggs were little exposed 

 to danger and stood in no great need of protection. They were likely 

 to be of little avail in an age in which the growing intelligence ol the 

 smaller animals may have greatly increased the danger in this 

 direction. 



As regards the great ocean reptiles of the period in question, their 

 vulnerable point was undoubtedly in their habit of egg-laying, since, 

 like their modern representatives, the turtles, they must have laid 

 their eggs on the shores — perhaps with some effort at concealment in 

 the sand — and left them to nature and fortune. The great land 

 reptiles were probably little if any more heedful, if we may judge 

 from the habits of existing land reptiles, whose small degree of care 

 is in part an outcome of later evolution. Again, those huge creatures 

 probably laid hut lew eggs certainly much fewer than the smaller 

 animals whose continued existence may be largely due to their 



