EXCRETORY SYSTEM
Echinoderms have no kidneys. They use diffusion to get rid of nitrogenous waste. This waste is mostly ammonia gas. Their eating habits depend on the species of echinodermata, and what they eat determines what they excrete. (www.mesa.edu) They get rid of waste through their anus or through their tube feet, by using their vascular system (hicksvilleschools.org).