Amphi"xus, neuropore, [220], [457]
Amphi"xus, notochord, [435], [436], [443]
Amphi"xus, pleural folds, [495]
Amphi"xus, septa between myomeres, [416]
Amphi"xus, somatic muscles, [409]
Amphi"xus, yolk, [485]
Androctonus, [53], [54], [372], [423]
Annelids, lateral sense-organs, [357], [367]
Ann"lids, nephric organs, [390]
Ann"lids, rigin of Arthropods from, [395]