oscules

Oscules are small openings found on the surface of sponges. These pores serve as the exit points for water that has circulated through the sponge's internal canals and chambers. Water enters the sponge through much smaller pores called ostia, which are distributed across the sponge's body. Inside the sponge, specialized cells called choanocytes, or collar cells, create a current that draws water in and filters out food particles. The processed water, along with waste products, is then expelled from the sponge through the oscules. The size and number of oscules can vary depending on the species of sponge and its environment. They play a crucial role in the sponge's respiration, feeding, and waste removal processes. The arrangement and appearance of oscules are sometimes used as a characteristic for identifying different sponge species.