ra thalictriformis, morphology of tendrils.

Dichaea, fertilisation mechanism.

Dichogamy, Delpino on.
-ignorance of botanists of, prior to publication of "Fertilisation of
Orchids."

Dick, Sir T. Lauder, Survey of Glen Roy by.

Dickens, quotation from.

Dickson, Dr.

Dickson, W.K.

Dicotyledons, Heer on oldest known.
-sudden appearance.

Didelphys.

Digestion, beneficial effect on plants.

Dillwyn, paper in "Gardeners' Chronicle."

Diluvium, tails of.

Dimorphism, in Cynips.
-Darwin on.
-difficult to explain.
-and mimicry.
-in parasitic plants.
-Wallace on.
-Walsh on.
-Weismann on Sexual.
-in Cicadas.
-flowers illustrating.
-Darwin knows no case in very irregular flowers.
-in Melastomaceae.
-in Linum.
-in eight Natural Orders.
-in Primula.
-apparent cases due to mere variability.
-explanation of.

Dingo.

Diodia.

Dioeciousness, origin of.

Dionoea, experiments on.
response to stimuli.
Curtis' observations on.

Dipsacus, F. Darwin on.

Dipterocarpus, survival during glacial period.

Direct action, arguments against.
-Darwin led to believe more in.
-Darwin's desire not to underestimate.
-Darwin's underestimates.
-facts proving.
-Falconer on.
-and hybridity.
-importance of.
-of pollen.
-variation and.

Direction, sense of, in animals.

Disease, Dobell on "Germs and Vestiges" of.

Dispersal, (see also Distribution), of seeds.
-of shells.

Distribution, Forbes on.
-Hooker on Arctic plants.
-of land and sea in former times.
-of plants.
-factors governing.
-of shells.
-Thiselton-Dyer on plant-.
-Wallace on.
-Blytt's work on.

Disuse, Darwin on.
-effect of.
-Owen on.

Divergence, Hooker on.
-principle of.

Diversification, Darwin's doctrine of the good of.

Dobell, H., letter to.

Dogs, descent of.
-experiment in painting.
-expression.
-habits.
-rudimentary tail inherited in certain sheep-.

Dohrn, Dr., visits Darwin.
-serves in Franco-Prussian war.
-extract from letter to.

"Dolomit Riffe," Darwin on Mojsisovics'.

Domestic animals, crossing in.
-Darwin's work on.
-Settegast on.
-variability of.
-treatment in "Variation of Animals and Plants."

Domestication, effects of.
-and loss of sterility.

Domeyko, on Chili.

Dominant forms.

Don, D., on variation.
-mentioned.

Donders, F.C., on action of eyelids.
-letters to.

Dorkings, power of flight.