A. aurita, [312]

Aureliania heterocera, [383]

Auricula, of Echinus esculentus, [526];

of Cidaridae, [531];

of Arbaciidae, [531];

of Echinarachnius parma, [546];

represented by radial pieces of calcareous ring of Holothuroidea, [566]

Auricularia, [607];

metamorphosis of, [614], [615]

Auronectidae, [301], [308]