234 



TABLE No. 30 

 RATE OF BORING OF BANKIA SETACEA IX SAX FRAXCISCO BAY 



TABLE No. 31 

 SUMMING UP TABLE 30 



It appears that each species has an optinium temperature for reproduction, 

 settlement of lar\-ae and growth, which in the case of Bankia setacea occurs in the 

 late winter and early spring, and in the case of Teredo navalis occurs in late summer 

 and early fall. Thus it is conceivable that the higher temperatures of sunmier might 

 prove as unfa\-orable to the growth of Bankia as the low temperatures of winter 

 are to Teredo. 



The last specimen listed in tables 30 and 31 is interesting as indicating the possi- 



