| Abstract: | Light and electron microscopic studies showed that the oral gland cells have two quite different zones. Medially, the basal zone is in contact with body fluids and the endostyle. Its strongly pyroninophile cytoplasm contains the extremely digitated nucleus and numerous small mitochondria. Laterally, the apical zone contacts the epidermis and it may also send a process between epidermal cells and deliver cell fragments into the primordium of the new house. This cell zone contains numerous membranes. It is concluded that the oral gland cells are light producing glands and that the membrane-rich cell fragments which are incorporated into the house wall are the source of the bioluminiscence which has been reported from empty houses. The ontogenetically related subchordal cells have a similar structure and it is possible that also these cells are light producers. |
