Aspidocotylea, [73]

Aspidogaster, [63], [73]

Aspidosiphon, [421], [423], [424], [425], [428];

commensalism of, [429]

Asplanchna, [200], [205], [210], [213], [215] n., [223], [226]

Asplanchnaceae, [203], [212], [220], [222]

Asplanchnidae, [200], [201], [203], [205], [211], [212], [216], [223], [226], [230]

Asplanchnopus, [201], [211], [222], [223], [226], [230]

Ass, parasites of, [140]

Association, of Rhabdocoels with Lamellibranchs and Sea-urchins, [45];