Palæo"traca, segments, compared to Ammocœtes, [308]
Pantopoda, glands, [423]
Parachordals, [121], [132], [377]
Parapodia, [357]
Parapodopsis, foot glands, [422]
Parathymus, [427]
Parathyroids, [427]
Parietal organ, [76]
Pecten of scorpion, [114], [359], [366], [371], [372], [373], [374]
Pedipalpi, [190]