Appe"dages, Trilobites, [351]

Apus, [28], [137], [436], [437]

Arachnids, eyes, [75], [87]

Arac"nids, diverticula of stomach, [109]

Arac"nids, lyriform organs, [364], [368]

Arac"nids, segmental excretory organs, [423]

Archæocytes, [473]

Artemia, v. Branchipus

Arthropleura, [249]

Arthropoda, arrangement of organs, [10]