[Localization of cholinesterase-Activity during gastrulation of the sea urchin embryo].

The localization of cholinesterase (ChE)-activity during gastrulation of the sea urchin embryo was investigated at the cellular level by histochemical methods.ChE-activity was found in primary and secondary mesenchyme cells and in the invaginating archenteron.In the course of development, ChE-activity disappears from primary mesenchyme cells.In very early pluteus stages the enzyme was located in all parts of the gutand in some of the free cells.The results are discussed in relation to the locomotory behaviour of the cells.