Strongylocentrotus franciscanus.

Svalof, agricultural station of.

Synapta, calcareous bodies in skin of.

THISELTON-DYER, SIR WILLIAM, on "Geographical distribution of Plants". --on Burchell. --on protective resemblance. --elsewhere.

THOMSON, J.A., on "Darwin's Predecessors. --elsewhere. --and P. Geddes.

Trifolium pratense quinquefolium.

Twins, artificial production of.

Variability, Darwin's attention directed to. --W. Bateson on. --and cultivation. --causes of. --polymorphic.