4 





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10 pm 



Figure 3. — Digestive diverticula of a copper "sick" oyster, Crassostrea virginica, from Raritan Bay. 

 Connective tissue cells surrounding the diverticula were greenish black, a positive reaction of copper 

 by the rubianic acid method. A scale of magnification appears in the lower right-hand corner of each 

 photomicrograph. 



659 



