Fig. 102. Young, yearling and two-year-old scallops. The small scallops 

 on the left are three months old "seed; " those in the center are eleven months 

 old, and have a growth line near the edge of the shell; while the large scallops on 

 the right are twenty-three months old, and have two growth lines, the second 

 being close to the edge of the shell. About one-half life size. 



