Text-fig. 10—a and b, Halecium beanii (Johnston). a, portion of polysiphonic stem with monosiphonic branch; b, male gonotheca; c and d, Halecium sessile Norman. c, female gonotheca, d, male gonotheca e–k, Halecium beanu (Johnston). e, female gonotheca, Chatham Island material, f, branches from monosiphonic region of erect stem, Woodpecker Bay, South Island; g and h, hydrothecae; i and j, male gonothecae; k, female gonotheca, Woodpecker Bay material.