The stomach opens into the gastrovascular system canals, which have a definite biradial arrangement. The roof of the
stomach opens into the aboral / infundibular canal that runs along the underside of the statocyst and gives out as 4 branches
the ‘excretory’ or anal canals (interradial). These canals terminate in ampullae, with two of them diagonally opposite each
other opening via ‘excretory’ pores, whilst the other two are blind. The ‘excretory’ pores eject indigestible matter and so are
actually anal pores.