Tidepool Tim says,  “Finger sponges are quite impressive - they look like a plant but are actually filter feeding animals.  We get most of our sponges from divers or fishing boats occasionally we will chance on some when collectng along the shores.  Finger sponges use tiny holes or oscula to sieve plankton from the cold waters here in our bay. Our sponge specimens are typically found attached to horse mussel shells or small stones.  The form of the animal is finger-like as the name suggests, but many we see are flat and palm-shaped. sponges look great in aquariums but we find it is hard to keep the alive for very long due to their food requirements.  Still they are a wondrous study specimens and one of great phylogenetic importance.”