Here I present: Tracy L. Lewis, “The Cell Biology of Sponges”, 2011 which was a textbook. The Poriferan (sponges) are the simplest invertebrates. Sponges consist of only 15 different cell types. This is in contrast to humans, which contain 211 cell types in the adult body. Thus, sponges are used in research as model organisms. Continue reading Tracy L. Simpson, The Cell Biology of Sponges”, 2011.