An oostegite is a large, flexible plate-like flap extending medially from the coxae (first segments) of the pereiopods (thoracic appendages) in some female crustaceans. It forms part of the marsupium or brood pouch of members of the order Peracarida. ...
• (n.) One of the plates which in some Crustacea inclose a cavity wherein the eggs are hatched.