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CHAPTERS ON EVOLUTION. 



(b, f) to our own times, presenting little or no change for the atten- 

 tion of the geological chronicler. The curious king-crabs or Limuli 

 (Fig. 244) of the West Indies are likewise presented to our view, with 

 little or no variation, from very early ages of cosmical history ; and 

 of the pearly nautilus (Fig. 247) now remaining as the only existing 

 four-gilled and externally shelled cuttlefish the same remark holds 



good. The fishes, like- 

 wise, are not without 

 their parallel instances 

 of lack of change and 

 alteration throughout 

 long ages of time. The 

 well-known case of the 

 genus Beryx presents 

 us with a fish of high 

 organisation, found liv- 

 ing in the Atlantic and 

 Pacific Oceans, and 

 which possesses fossil representatives and facsimiles in the chalk 

 (Fig. 245). From the latter period to the present day, the genus 

 Beryx has therefore undergone little modification or change. The 

 same remark certainly holds good of many of those huge " dragons 



FIG. 245. BERYX. 



FIG. 246. ICHTHYOSAURUS (A) AND PLESIOSAURUS (B). 



of the prime " (Fig. 246), which revelled in the seas of the trias, 

 oolite, and chalk epochs developed in immense numbers in these 

 eras of earth's history, but disappearing for ever from the lists of 

 living things at the close of the cretaceous age, and exhibiting little 

 or no change during their relatively brief history. 



Such cases of stability amidst conditions which might well have 



