Sponge - A beautiful Haliclona sp. specimen from Chek Jawa, Singapore. Haliclona permollis showing multiple chimneys of a single individual sponge. Seawater is pumped continuously through a sponge by the beating activity of flagella that line the internal cavities. Water is drawn into the sponge through many small intake openings located on the outside surface and is released from exhalent openings on chimneys and vented away.
Either something just took this guy by surprise, or he's an underwater Cookie Monster look-a-like! This Caribbean sea creature is called the stove-pipe sponge. (photo: MAURICIO HANDLER/NAT GEO CREATIVE/CATERS NEWS)