sycon

The sycon type of water-current system is a physiological characteristic found in some sponges, particularly within the Calcarea class. This system is crucial for the sponge's survival, facilitating the intake of food and oxygen and the removal of waste products.

In a syconoid sponge, water enters through pores directly into fingerlike projections of the sponge wall. These projections contain choanocytes, or collar cells, which generate water currents and capture food particles. The water then moves into a central cavity, the spongocoel, and exits through an opening called the osculum. In more complex syconoid structures, incurrent canals may lead water to the radial canals, where the choanocytes are located, before it enters the spongocoel.1

Sponges, including those with syconoid systems, are typically hermaphroditic, meaning they can produce both sperm and eggs, though often at different times to avoid self-fertilization. Sperm are carried by water currents to other sponges, where choanocytes assist in fertilization. Sponges can also reproduce asexually through methods like gemmulation, where cell aggregates are encased in a protective covering and can survive unfavorable conditions.23