development of, in Asterina gibbosa, [611];
in Holothuroidea, [615];
in Antedon rosacea, [619]
Radial fission in Volvocaceae, [110] f.
Radial nerve-cord, of Asterias rubens, [444], [445], [446], [447];
of Ophiothrix fragilis, [488];
of Echinus esculentus, [518], [519], [522];
of Holothuria nigra, [566];
of oral system of Antedon rosacea, [584];