STRUCTURE OF THE VERTEBRATES 



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like fossil (Palaeospondylus) is known from the middle of the 

 Palaeozoic. 



The following tables, beginning with the oldest vertebrate era, 

 are divided into Periods or major divisions; while the last table, 

 covering the Cenozoic, is further divided into Epochs. The 

 Cenozoic is the age of the rise of mammals and is of most 

 interest in the evolution of man. In these tables dominant life 

 refers to the plants and animals which are (1) most abundant; 

 or (2) had reached the highest degree of specialization, with 

 particular reference to the vertebrate line. It is not inferred 

 that the invertebrate phyla were not represented. 



Palaeozoic Time 



