of Echinarachnius parma, [546]
Tooth-papilla, of Ophiothrix fragilis, [482];
of Ophiocoma, [493];
of Ophiocomidae, [499]
Tornaria, [616]
Torquatella typica (= Strombidium), [155] n.
Torus angularis, of Ophiothrix fragilis, [482]
Toxa (= a bow-shaped spicule without spiral twist), [222]
Toxaspire (a spiral rod in which the twist a little exceeds a single revolution. The pitch of the spiral being great the spicule appears bow-shaped), [222]