pylomes, [64];

dimorphism, [67];

monstrous shell, [69]

Orbulina, [59], [66];

O. universa, [68]

Orbulinella, habitat, [75]

Organ-pipe Coral, [343]

Organella, [44] n.

Organic compounds, their function in nutrition, [35] f.

Organoid, [44] n.