52 



Our Food Mollusks 



As might be expected, all localities are not equally 

 favorable for the growth of these plants. Temperature 

 has much to do with the rate of their multiplication. 



Fig. 12. — Diatoms found in the stomachs of oysters. (From the 

 U. S. Bureau of Fisheries.) 



They are numerous enough in the cold waters of the At- 

 lantic coast above Cape Cod to support large areas of 

 long neck clams, but their numbers are much greater in 



