Operculum of central capsule of Phaeodaria, [76], [82]

Ophiacantha, [492], [499];

mouth-frame, [492];

O. chelys, [499]

Ophiactis, [498];

O. balli, [498];

O. virens, [491], [498]

Ophiarachna, [481], [499]

Ophicephalous pedicellariae, of Echinus esculentus, [508];

of E. acutus, [509];