Structure, histochemistry and formation of the podocyst and cuticle of Aurelia aurita

At the junction between the scyphistoma's scyphopharynx-filament complex and its endoderm is a narrow zone of simple columnar cells. These cells can transform into amoebocytes which collect together and work their way to the aboral end of the polyp, where they secrete a cuticular encasement, thus forming the podocyst. Light and electron microscopy, as well as histochemistry, show the podocyst to be a lamellated tanned chitin-protein complex covering the protoplasmic contents, which have a nucleated outer clear cytoplasmic layer and a yolky central zone which may be liquefied in places.