Peridiniales, synonym of Dinoflagellata used by Schütt, [119], [132]
Peridinium, [110];
fossil, [132];
P. divergens, [131]
Perigonimus, [265], [266], [269]
Perihaemal spaces (or canals), of Asterias rubens, [448];
of Ophiothrix fragilis, [481], [488];
of Echinus esculentus, [524];
of Holothuria nigra, [566]
Peripatus, segmentation of, [32] n.