OF EVOLUTION. 95 



belong, which the fossil fauna of Florida has 

 permitted me to complete. They range back in 

 time from the present era to the Miocene, or 

 possibly even a still older, period, and comprise 

 each some four or five hitherto described species 

 and two or three new forms which are now for 

 the first time brought to light. In other words, 

 they represent some six or seven distinct species 

 of systematists, yet so closely do they grade 

 one into the other that it is impossible to 

 define the individual limits, and they may be 

 properly considered to represent one true or 

 varying type. Is not this a remarkable instance 

 of specific variation and origination, or is it 

 merely a matter of blind coincidence ? 



It might very naturally be contended that in 

 assuming the Pliocene fossils here represented 

 to be the ancestral forms of some of the living 

 species the assumption is in the nature of a 

 thing taken for granted, and that no reasonable 

 proof has been presented indicating the neces- 

 sary changes from the extinct to the recent 



