w describes new species from Galapagos.

Orang-utang, Rolleston on brain of.
-Wallace on.

Orange trees, grafting of.

d'Orbigny, on geology of S. America.
-theory of formation of Pampas mud.
-"Voyage dans l'Amerique meridionale.
-mentioned.

Orchids, adaptation in.
-Darwin's work on.
-Darwin's view that seedlings are parasitic on Cryptogams.
-Falconer's estimate of Darwin's work on.
-few species in humid temperate regions.
-flourish in cool temperate regions.
-illustrate diversity of means to same end.
-monstrous.
-quoted as argument against species arising from monstrosities.
-utility and.
-fertilisation mechanisms of.
-Brazilian.
-Darwin decides to publish his work in book-form.
-Darwin sends copy of his book to F. Muller.
-Darwin underrates power of producing seeds without insects.
-French translation of Darwin's book.
-germinative power of pollen.
-Hildebrand's paper on.
-Nectar not excreted in some English.
-and nectar secretion.
-formation of ovule after pollination.
-Scott points out error in Darwin's work.
-Scott on pollen-tubes of.
-Scott on self-sterility.
-self-fertilisation in.
-setting of seed in unopened flower.
-sterility of.
-course of vessels in flowers.
-wonderful contrivances intelligible.

Orchis, flowers of.
-nectaries of.
-pollinia of.

Orchis (Bee) (see also Ophrys apifera), Darwin's experiments on.
-O. pyramidalis, fertilisation mechanism.
-O. ustulata.

Order of Nature.

Ordination.

Organ mountains, Darwin on plants of.
-glacial action on.

Organisms, simultaneous change in.
-amount of change in fresh water and marine.

Organs, transition of
-use of.

"Origin of the Fittest," Cope's.

"Origin of Genera," Cope's work on.

Origin of life.

"Origin of Species," acceptance of doctrine of Evolution due to the.
-Darwin's belief in the permanence of the framework of the.
-Darwin's opinion of his book.
-Dawson's review of.
-direct action underestimated in the.
-editions of the.
-errors in.
-Falconer's estimate of.
-Huxley's Cambridge speech, and reference to the.
-Huxley's lecture on coming of age of.
-Huxley's review of.
-Lesquereux's articles in "Silliman" against the.
-publication of the Abstract of.
-publication by Murray of.
-sale of the.
-Seemann on the.
-translation of.
-Wallace's criticism of.
-Walsh on the.
-Darwin on necessity for modifications in the.
-review by Flee