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NEW YORK STATE MUSEUM 



and at sometime, an opportunity will be afforded for the study 

 of pre-Cambrian life. West of the Kocky mountains, stratified 

 deposits of great thickness are known beneath rocks of Cambrian 

 age and these may, in time, when carefully searched, yield an 

 abundant fauna. 



Development of Life 



ANIMALS 



In classifying the animal kingdom, we find that by the presence 

 or absence of an important feature it is possible to place most of 

 the forms in two great sub-kingdoms : the invertebrates and the 

 vertebrates; those without a backbone and those possessing one. 



The animals without backbone are considered lower in the 

 scale of development, as they have, in general, less intelligence 

 and fewer resources. They are usually dependent for protection 

 on an external skeleton or armor which encloses their soft bodies. 



The vertebrate animals are, in general, characterized by rela- 

 tively higher intelligence and have, at their command, more ways 

 of protecting themselves and securing a living. The soft parts of 

 their bodies are built around a bony skeleton and they depend 

 for self protection more generally on their activity and intelli- 

 gence than upon mere mechanical means of protection such as 

 shells or armor. 



Among the invertebrates the cuttlefishes, were and are still 

 the most highly developed type in regard to size and power though 

 the crustaceans are considered to be more highly organized; 

 among the vertebrates, man is supreme. 



As we do not know the whole history of life development, we 

 cannot show accurately in a diagram or scheme the relations of 

 the different groups. The older arrangement which is still used 

 in many text-books of geology is as follows: 



