抄録
The calcareous skeletons of many invertebrates contain micro-growth banding patterns. The
clam lays down weak micro-growth bands in the shell. The clams were cultivated under three
different immersed conditions and band patterns in the shell were statistically compared. The
group A was immersed except at semi-diurnal low tide, group B was out in air at lowest sea level
in high tide and group C was kept always below sea surface throughout the experiment. No
numerical difference was found in the growth band number between the shell. All clams
subjected to a 66 minute period seich in the band as well as semi-diurnal and diurnal tidal periods.
