The Survival of tJic Fittest 



competitors whole, so that this lack was no seri- 

 ous defect. 



Crustacea, now represented by crabs and lob- 

 sters, crept or swam, had jointed legs, and were 

 protected by a coat of plate-armor. 



Swimming in the water above were some ani- 

 mals, probably about as large as good-sized 

 earthworms. They had no defensive armor, and 

 no weapon of offense. They had been driven 

 from the rich feeding grounds of the bottom by 

 the crabs and mollusks, and were living on the 

 minute forms of life which they could sift from 

 the water. These were the first vertebrates. 

 There must have been other interesting forms; 

 there were probably many peculiar and fascinat- 

 ing worms. But these w^e can pass by. They 

 have mostly become extinct. 



Which of these three competitors is the fittest? 

 The free-swimming primitive vertebrate seems 

 to be already distanced in the race. The crab is 

 a well-protected, moving being, whose jointed 

 legs promise a higher organization. But the 

 cuttlefishes have everything their own way. 

 They are completely protected, and that seems 

 to count for most under present conditions. 

 They move fairly well. They have abundance 



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