Sponge Geodia cydonium (Lat. Geodia cydonium). It inhabits lagoons, caves and coastal detritus. It is a large sponge built of a large number of lobes and in the central part, larger individuals develop a central depression in the form of a large osculum. It usually reaches a size of about 30 cm, although it can also reach a size of 50 cm in diameter. The colour is sometimes difficult to notice due to the amount of sediment and fouling on the body, but it mostly varies from yellow to beige. Their body is firm and compact. Due to the presence of spicules that expose the outside, the surface of the body can be thorny. Due to its structure, it serves as a hiding place for many invertebrates. The species is protected in Montenegro.