Collar cells are a flagellated cells that pump water into a sponge.
- ↑ Sponges feed by filtering small food particles (some even eat bacteria) out of water pumped through the system by flagellated collar cells. (See Sponges: Animals without Backbones)
- ↑ Wile, Dr. Jay L. Exploring Creation With Biology. Apologia Educational Ministries, Inc. 1998