About Clathrina clathrus (Schmidt, 1864)
Clathrina clathrus (Schmidt, 1864) is a species of calcareous sponge in the family Clathrinidae. This sponge is typically yellow, though it may occasionally be white. It can grow up to 10 centimeters in diameter, and usually looks cushion-shaped when viewed from a distance. This is in contrast to its close relative Clathrina coriacea, which is normally flatter. When viewed up close, Clathrina clathrus is made up of a tangled mass of tubes. These tubes are thicker and less tightly connected than those of C. coriacea, and Clathrina clathrus lacks the osculum that is present in C. coriacea. Like C. coriacea, the spicules of Clathrina clathrus are exclusively three-pointed triactines. It is a shallow-water species that occurs in the Mediterranean Sea and along the Atlantic coasts of Europe, ranging as far north as the British Isles.
