PLATE 5 



EXPLANATION OF FIGURES 



Chaetopterus. Development in KNC and HCl 



19 A B Larval form showing differential inhibition and partial recovery. 

 KNC eleven hours, beginning forty-five minutes after fertilization; then returned 

 to sea water. 



20 A B Development in HCl m/2500 from thirty minutes after fertilization. 

 A lateral, B ventral view. 



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