Orthite, ix, 376.
Orthocerata, see [Zoology, Mollusca.]
Orthography, English, proposals for improving, xxxix, 197.
Orycterotherium, xlii, 136f, 392; xliv, 69f; xlv, 210.
— Missouriense, xliv, 69f; xlv, 210.
— Origonense, xlii, 136f; xliv, 79.
Osborn, M. W. and N. S., on a vibrating dam, xliv, 366.
Osler, F., on indications of his anemometer, xxxviii, 103.
Osmelite, xv, 388.
Osmium, atomic weight and compounds of, E. Fremy, xlix, 199.