f the
fittest."
-letter to.
-on electric organs.
-on genesis of nervous system.
-on survival of the fittest.
-Romanes on his theory of nerve-genesis.
-Wallace's admiration for.
-Darwin on his work.
-extract from letter to.
-mentioned.

Spermacoce.

Spey, terraces of.

Sphagnum, parasitism of orchids on.

Spiders, mental powers of.
-Moggridge on.

Spiranthes, fertilisation of.

Spiritualism, Darwin on.

Sptizbergen, Lamont's book on.
-reindeer of.

Sponges, Clark on classification of.
-Hackel's work on.
-F. Muller on.

Spontaneous generation.
-Darwin's disbelief in.
-Huxley's disbelief in.

Sports.

Sprengel, (C.C.) Christian Konrad (1750-1816): was for a time Rector of
Spandau, near Berlin; but his enthusiasm for Botany led to neglect of
parochial duties, and to dismissal from his living. His well-known
work, "Das Entdeckte Geheimniss der Natur," was published in 1793. An
account of Sprengel was published in "Flora," 1819, by one of his old
pupils. See also "Life and Letters," I., page 90, and an article in
"Natural Science," Volume II., 1893, by J.C. Willis.
-on Passion-flowers.

Stag-beetle, forms of.

Stahl, Prof., on Desmodium.
-on transpiration.

Stainton.

Stanhope, Lord.

Stanhopea, fertilisation of.

Stapelia, fertilisation of.

Starling, paired three times in one day.

State-entomologist, appointment of in America, not likely to occur in
England.

Statistics, of births and deaths.
-Asa Gray's N. American plant-.

Steinheim, Lias rocks of.

Stellaria media, cross-fertilisation of.

Stephens, Miss Catherine: was born in 1794, and died, as the Countess of
Essex, in 1882.

Sterile, use of term.

Sterility, accumulation through Natural Selection.
-arguments relating to.
-artificial production of.
-between allied species aided by Natural Selection.
-connection with sexual differentiation.
-and crossing.
-domestication and loss of.
-experiments on.
-of hybrids.
-in human beings.
-Huxley on.
-increase of races and.
-laws governing.
-Natural Selection and.
-in pigeons.
-in plants (see also self-sterility).
-reciprocal crosses and unequal.
-selection and.
-variations in amount of.
-varieties and.

Stirling, and Huxley.

Stokes, Sir G.

Strasburger, on fertilisation of grasses.

Stratification, and cleavage.

Strephium, vertical position of leaves.

Strezlecki.

Strickla