Regeneration of the cell mass in larvae of temnopleurid sea urchins

Mechanisms of cell mass (CM) formation were analyzed by microsurgery in two temnopleurid sea urchins, Mespilia globulus and Temnopleurus toreumaticus . The CM in temnopleurids is formed at the early larval stage from the left ectodermal invagination, and with the hydrocoel derived from the mesoderm, forms an adult rudiment. After serial removal of the CM, it was strongly regenerated until its attachment to the hydrocoel, with the same timing as...