262 ANIMAL AGGREGATIONS 



facts indicate that not all animals whose groups show survival values 

 are to become more closely social, but that animals, whatever their 

 endowments, could not have developed the social habit had the 

 incipient social stages lacked the type of survival values which we 

 have repeatedly demonstrated for different sorts of animals, and 

 now also for bacteria. These values are a function, other conditions 

 being equal, of the mass of animals in relation to the volume of 

 their effective environment. 



