At 52 hours, two myocytes of the LRM are noticeably larger than the other six, and these two alone make direct contact with shell field epithelial cells that will eventually form the attachment plaque onto the shell.
At 52 hours, the basal ends of these myocytes reach toward their definitive anchorage site on the protoconch, but a differentiated attachment plaque is not yet recognizable.
The attachment plaque of the LRM is located slightly toward the left side of the postrotational shell, whereas the attachment plaque of the ACC has a more ventro-medial location within the bowl of the protoconch.
Tensile forces are transmitted longitudinally by the endto-end contacts across the Z-discs bounding the safcomeres and across the attachment plaques connecting between cell ends.
The detached sarcomeres remain interconnected serially like vertebrate myofibrils, through dense bodies and attachment plaques between cells.