| No annulations on the perisarc were seen and no gonophores were observed. |
| The myonemes of these cells attach to the mesoglea and to the exterior perisarc. |
| Here, a marine hydroid perisarc of Aglaophenia latirostris was investigated to understand how nature designs a stiff, tough and lightweight sheathing structure. |
| These cells are anchored to the perisarc and pull on the mesoglea, which becomes thickened. |
| The genera are based upon these differences in the perisarc. |
