Acanthocephala, [123], [124], [174] f.;
embryology, [179];
classification, [181]
Acanthocotyle, [73]
Acanthodrilidae, [357], [362], [381], [383], [384]
Acanthodrilus, [356], [363], [366], [372], [382], [384];
chaetae, [350]
Acanthozoon, [20]
Accessory gut, of Polychaeta, [305]
Aceros, [19]