Papula

{{Short description|Projections of the coelom of Asteroidea}} {{for|the skin condition|papule}} {{one source|article|date=April 2025}} '''Papulae''' (sing. '''papula'''; also occasionally '''papulla, papullae'''), also known as '''dermal branchiae''' or '''skin gills''', are projections of the coelom of Asteroidea that serve in respiration and waste removal.<ref>{{Cite journal |last=Shick |first=JM |last2=Edwards |first2=KC |last3=Dearborn |first3=JH |date=1981 |title=Physiological Ecology of the Deposit-Feeding Sea Star Ctenodiscus crispatus: Ciliated Surfaces and Animal-Sediment lnteractions |url=https://doi.org/10.3354/meps005165 |journal=Marine Ecology Progress Series |volume=5 |pages=165–184 |doi=10.3354/meps005165 |issn=0171-8630|url-access=subscription }}</ref> Papulae are soft, covered externally with the epidermis, and lined internally with peritoneum. They extend through the mesodermal ossicles and are protected from microscopic larvae by pedicellariae. In a living specimen, the dermal gills can be extended or withdrawn.

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Category:Echinoderm anatomy