Origin of the Spicule Skeleton of Fresh Water Sponges (Spongillides)

摘要

Young fresh water sponges cultivated in the laboratory in constant temperature water and in ambient temperature were used to study the origin of the sponge spicule skeleton. The SiO2 spicules are formed in scleroblasts. Aged spicules leave the scleroblasts and are transported by transport cells to their functional location where they adhere to the base plate through epongin which ensures their stability. The life cycle of the spongilides throughout the seasons is described. The influence of gravity on the development of young sponges should be studied.