Fig. 5.—

Whole mount ISH results. Images position the oral end of the gonophores/medusa toward the top. Arrows mark regions of concentrated expression at the distal end of the bell axis or the oral end of the developing manubrium. Only male Hydractinia symbiolongicarpus sporosacs are shown as eggs in females block the view of the spadix (manubrium anlage). Inset in Hox1, stages 7–9 pane is a view from the oral end of the gonophore looking down. ec, ectoderm; en, endoderm; ent, entocodon; gt, gametic tissue; ma, manubrium, oc, oocytes; rac, radial canal; ric, ring canal; sm, smooth muscle; spa, spadix; str, striated muscle; tb, tentacle bulb; ve, velum.