obsolete epitheloid monolayer of cells 2011-04-22T06:50:20Z Sponge cells adhere to form tissue-like layers, but a true epithelial cell layer, characterized by aligned cell polarity, belt-form junctions and underlying basal lamina, is thought to be a eumetazoan innovation. Amphimedon possesses all the main components of the Par, Crumbs and Discs Large (Dlg) complexes, a set of interacting proteins that are largely metazoan-specific and determine polarity in epithelial cells[http://www.nature.com/nature/journal/v466/n7307/full/nature09201.htm] cjm true