Question

During torsion in molluscs the site of body which is most affected

Answer 1

180° anticlockwise twisting of the visceropallium on the head-foot long axis during early development in gastropod mol­luscs is torsion. It is an early and fundamen­tal event in gastropod ontogeny (the event in phylogeny, which brought the gastropod in being). Most of the organs are affected by torsion and certain structures initially lodged posteriorly are brought to the front.

A narrow neck behind the head connects the head-foot and visceropallium, through which runs the oesophagus, rectum, anterior aorta, visceral loop and muscles attached to the shell. The short, narrow neck is the site of torsion