^^ THE NEW EVOLUTION "^^"^ 



all types of animal life must be explained in terms of 

 a primitive single cell. The seemingly simultaneous 

 appearance of all the phyla or major groups of ani- 

 mals simply means that life at its very first be- 

 ginnings developed at once and simultaneously from 

 the primitive single cell in every possible direction, 

 giving rise to some original form or forms in every 

 phylum. 



So at its very first appearance animal life assumed 

 essentially the same form as that in which we know 

 it now so far as the phyla or major groups of animals 

 are concerned. That is, at the very beginning there 

 appeared a representative or representatives of the ar- 

 thropods (figs. 7-32., pp. zi, 33, 47 and 55), the jointed 

 worms or annelids (fig. 85, p. 161), the mollusks (figs. 

 45-51, p. 97), the arrow-worms or chastognaths (fig. 

 Gz, p. Ill), and so on. There is no evidence whatever 

 that would lead us to believe otherwise. 



As age succeeded age the forms within these major 

 groups underwent constant and continual change. 

 For instance, in the arthropods the trilobites (fig. 31, 

 p. 55) and the eurypterids (fig. 31, p. 55) increased in 

 diversity and then died out, giving place to a wealth 

 of other types developed from other lines within the 

 phylum. But the characteristic features of the phy- 

 lum as a whole remained unchanged. 



Thus the evolutionary picture that we get from a 

 survey of the actual facts is that at the very first there 

 were numerous basic forms from each of which a 

 separate evolutionary tree arose growing upward 

 through the ages. The topmost twigs of each of 



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