Mechanical Senses and the Tunic Structure in Halocynthia roretzi

摘要

It was previously mentioned that the mechanical stimulus (touch) caused the active movements of the tunic in Halocynthia roretzi, a solitary ascidian. However, how the direction of the mechanical stimulus is important, and what helps the tunic to have mechanical senses, have not been clear. In this study, whether or not rubbing the tunic outermost surface caused the active deformation, and the structural difference between the outermost surface and other regions, were examined. The rubbing caused the tunic deformation as the touching did. The outermost surface was different from the other regions structurally, and varied by the portion.