In Cirripedia (Acrothoracica), pair of chitinous thickenings (best developed in Cryptophialidae) running from chitinous apertural thickenings medially down each side of mantle sac [Moore and McCormick, 1969].
(Subclass Cirripedia):
In acrothoracican, pair of chitinous thickenings reinforcing each side of mantle; extends from aperture halfway down body [Stachowitsch, 1992].
(Superorder Acrothoracica):
Pair of external chitinous thickenings extending from apertural thickenings medially down each side of mantle sac [McLaughlin, 1980].
Crustacea glossary. Natural History Museum of Los Angeles County. 2011.