Sept. 8, 1900. 



^te 



Sept. 20, 1900. 



Sept. 20, 19 



Fig. 12.— Clams set in the summer of 1900 in clam catcher, and raised in sand boxes. 

 The various specimens, taken at intervals, represent their growth during two years and 

 a half. (Sec page 3L.) The difference in size of the two specimens on Sept. 20 1900, is due 

 to the difference in locality. 



