When alive, its color is dark grey; upon drying it becomes either yellow or brown. Young larvae swim freely until they attach themselves to the sea floor or other adequate ground. After that, they start growing slowly, as it may take as much as 40 years to grow the size of a baseball
1 bath sponge or Spongia officinalis
2 Suberites domuncula
3 hermitcrab
4 Sycon raphanus