of Echinus esculentus, [516];
of Holothuria nigra, [563];
of Antedon rosacea, [583];
of Actinometra, [589];
of Dipleurula, [605];
of Protocoelomata, [616]
Intracapsular protoplasm of Radiolaria, [80] f.
Intramolecular respiration, [14] n.
Intranuclear spindle of Euylypha, [29]
Invertebrata, hosts of Gregarines, [97] f.