A perforated plate by which the entry of seawater into the vascular system of an echinoderm is controlled.
- ‘The water vascular system generally has one madreporite.’
- ‘The madreporite was not visible until the juveniles were about 10 mm diameter and all the arms were of similar size.’
- ‘The water vascular system of the sea stars open up at the madreporite, a perforated opening in the central part of the animal.’
- ‘One of the genital plates serves as the sieve plate, or madreporite, for the water vascular system.’
- ‘Virtually all extraxial body wall in asteroids is of the perforate variety, since it includes body openings such as papular pores, hydropores in the madreporite, gonopores, and the anus.’
Early 19th century: from madrepore (see Madreporaria) + -ite.