THE ROYAL NATURAL HISTORY. 



INVEBTEBBATE ANIMALS. 



CHAPTER I. 

 THE JOINTED ANIMALS, Subkingdom ARTHROPODA. 



THE INSECTS, Class Insecta. 

 ANTS, WASPS, BEES, ETC., Order HYMENOPTERA. 



IN the early days of zoological science, when the value in classification 

 between Verte- of the structural and embryological characters of living beings was 

 brates and in- b u t little understood, the animal kingdom was divided into two 

 subkingdoms called Vertebrata and Invertebrata ; the former embrac- 

 ing those forms provided with a vertebral column, or backbone, and the latter those 

 that were not so provided. With the addition of some few classes, whose organ- 

 isation has only recently been fully comprehended, the Chordata of to-day are 

 coextensive with the Vertebrata of half a century ago. But the term Invertebrata, 

 as denoting a natural assemblage of animals, has long ceased to be used by every 

 competent zoologist, and is nowadays merely applied as a conveniently vague title 

 for all the animals that have not acquired the characters of the Chordata. This 

 change of opinion has been brought about by the attainment of a far more intimate 

 acquaintance with the structure and development of the lower animals than our 

 predecessors, with their less refined methods of investigation, could possibly 



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