Jan. 17, 1903. 



Oct. 20, 1903. 



Fig. 13.— 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 three years 

 and four months. The difference in size of the two specimens on Sept. 20, 1900 is due 

 to the difference in locality. ' 



