spermatozoa, [87];
tentacular apparatus, [88];
vertebrae, [86];
visceral arches, [86]
Archaeopteryx, [417]
Archegosaurus, vertebrae, [13], [82], [287]
Arcifera, of Cope, [140];
of Boulenger, [140]
Arciferous, type of shoulder-girdle, [24], [25]
Arion, slug, eaten by tortoises, [363]