Zoœcia large, subpyriform, with broad margins sloping slightly inwards and expanding at the foot into a short front wall; areas elliptical, length ·5 to ·75 mm., breadth ·31 to ·45 mm., tapering towards the head, across which stretches a slight internal shelf, which straightens the apparent outline; from the edge of this shelf hangs a stout oval ring, which connects it with the floor of the zoœcium; zoœcial boundaries distinct.