Histology
The histological technique was as follows: whole clam soft tissue
was removed from the shell, transverse section was cut in
the middle of the body to allow fixative to penetrate tissues
and tissue was preserved in Davidson’s fixative solution for
24 h, dehydrated with graded ethanol, cleared with xylene,
embedded in paraffin wax and sliced to 5 lm transverse sections
at different organs using KD-2258 rotary microtome
and stained with Harris’ Hematoxylin–eosin and examined under
light microscope. Photos were taken using microscopeequipped
digital camera.