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THE BRITISH NATURALIST. 



245 



communities of social bees and wasps being, despite the diversities of 

 structure and function which obtain within them, only large families, 

 the descendants of one female. Nevertheless, except by an arbitrary 

 limitation of the meaning of the term, it is impossible to deny 

 that social instincts are possessed by many ants, bees, and wasps ; 

 storage of food, care of young, the construction of elaborate dwellings 

 (nests or burrows) ; the capture and breeding of aphides by ants, in 

 order to secure the honey-dew from them, all prove the possession by 

 these animals of instincts which tend to foster sociality within the 

 species. 



Passing to the vertebrate sub-kingdom, we find that true sociality 

 here, as amongst Arthropods, is restricted to the higher groups, and is 

 by no means universal, even in those higher groups. Favourable con- 

 ditions, either in the surrounding medium or of food supply, may lead 

 to the aggregation of enormous numbers in a limited space, but few 

 only of such aggregations develop into social groups. Sexual attraction 

 may lead to temporary companionship ; but neither amongst fishes nor 

 batrachians, which constitute the lowest and represent the ancestral 

 types of vertebrate animals, do we find any trace of social organization. 

 At a higher level, amongst the reptiles, we still fail to detect anything 

 which can properly be called sociality ; hibernating snakes are often 

 found in curious bundles ; turtles, at the breeding season, occur plenti- 

 fully in particular localities ; but these phenomena are due to external 

 conditions, and are in no sense social. Even in the upper division of 

 the Sauropsidan class, amongst the birds which have arisen from the 

 lower reptilian group, sociality is the exception rather than the rule. 

 Love of mates and of offspring is usually highly developed, but sexual 

 jealousy and the prolonged companionship of mates has fostered family 

 and individual at the expense of social development. In some species, 

 however, aggregations, perhaps originally due solely to favourable con- 

 itions of environment, proved to be of defensive value, and have 

 developed into societies, whose members, though they may have 

 "requent quarrels amongst themselves, yet will unite against a common 

 enemy, and carry on much of their life-work in harmonious co-operation. 

 The common rook is a familiar example of a social bird. The dwellers 

 n a rookery fight amongst themselves, and rob one another without 

 cruple ; but they will speedily unite to drive away any feathered foe. 

 hey usually feed together, and if surprised or endangered during their 

 epast the whole flock take to flight. They seem to have some rudimen- 

 ry notions of justice and of social organization, though I should 

 ertainly not urge as evidence of the latter that the flock, before 

 lighting in a field, post one as sentry on a tree, from which he 

 an command a good view and warn his comrades of any approaching 

 eril. I have often watched rooks feeding, and it is* certainly 



