Common Bay inhabitants in this group are the sponges. A sponge absorbs bacteria and dead plant and animal matter as the particles flow through its porous body. Phylum Molluska Invertebrates in the Phylum Molluska are soft-bodied animals. Common Bay inhabitants in this group are the clams and mussels. Clams and mussels are filter feeders, filtering out microscopic plants and animals floating in the water.
Clams move about by using a hatchet-shaped foot to creep along the muddy bottom of the Bay.
The sticky threads are produced from a gland near their foot. Phylum Annelida Invertebrates in the Phylum Annelida are segmented worms. A common bay inhabitant in this group is the tube worm. Tube worms live in brown mud tubes that the worms make from a mucus and mud mixture. The tube worm is not native to San Francisco Bay, it was introduced in the 1800's with the oysters brought over from the east coast to start an oyster industry in the Bay.