of. Dewar, on immersion of seeds in liquid
hydrogen.

Thlaspi alpestre, range of.

Thompson, Prof. D'Arcy, prefatory note by Darwin to his translation of
H. Muller's book.

Thompson, W., natural-historian of Ireland.

Thomson, Sir W., see Kelvin, Lord.

Thomson, Sir Wyville, on Natural Selection.
-mentioned.

Thomson, review of Jordan's "Diagnoses d'especes" by.

Thorns, forms of.

"Three Barriers," theological hash of old abuse of Darwin.

Thury on sex.

Thwaites, Dr. G.H.K. (1811-82): held for some years the post of Director of
the Botanic Gardens at Peradenyia, Ceylon; and in 1864 published an
important work on the flora of the island, entitled "Enumeratio Plantarum
Zeylaniae."
-on Ceylon plants.
-letters to.
-on the "Origin."

Thymus.

Tieghem, Prof. van, on course of vessels in orchid flowers.
-on effect of flashing light on plants.

Tierra del Fuego, flora of.
-comparison with Glen Roy.
-evidence of glaciers in.
-micaschists of.

Time, and evolutionary changes.
-geological.
-meaning of millions of years.
-Niagara as measure of geological.
-rate of deposition as measure of.
-Wallace on geological.

"Times," article by Huxley in.
-letter by Fitz-Roy in.

Timiriazeff, Prof.

Timor, Mastodon from.

Toad, power of Indian species to resist sea-water.

Tobacco, Kolreuter on varieties of.

Todd, on Solanum rostratum.

"Toledoth Adam," title of book on evolution by N. Lewy.

Torbitt, J., experiments on potatoes, and letter to.

Torquay, Darwin's visit to.

Tortoises, conversion of turtles into land-.

Tortugas, A. Agassiz on reefs of.

Toryism, defence of.

Toucans, colour of beaks in breeding season.

Trachyte, separation of basalt and.

Tragopan.

Traill, experiments on grafting.

Transfusion experiments, by Galton.

Translations of Darwin's books.

Transplanting, effect on Alpine plants.

Transport, occasional means of.

Travels, Bates' book of.
-Humboldt's.
-Wallace's.

Travers, H.H., on Chatham Islands.

Trecul, on Drosera.

Trees, herbaceous orders and.
-occurrence in islands.
-older forms more likely to develop into.
-Asa Gray on.
-conditions in New Zealand favourable to development of.
-crossing in.
-separate sexes in.

Treub, M., on Chalazogamy.

Treviranus, Prof., on Primula longiflora.

Trifolium resupinatum, Darwin's observations on bloom on leaflets.

Trigonecephalus.