Wheat, varieties of, 113.

White Mountains, flora of, 365.

Wings, reduction of size, 134.

Wings:  of insects homologous with branchiae, 191. rudimentary, in insects, 451.

Wolf:  crossed with dog, 214. of Falkland Isles, 393.

Wollaston, Mr.:  on varieties of insects, 48. on fossil varieties of land-shells in Madeira, 52. on colours of insects on sea-shore, 132. on wingless beetles, 135. on rarity of intermediate varieties, 176. on insular insects, 389. on land-shells of Madeira, naturalised, 402.

Wolves, varieties of, 90.

Woodpecker:  habits of, 184. green colour of, 197.

Woodward, Mr.:  on the duration of specific forms, 293. on the continuous succession of genera, 316. on the succession of types, 339.

World, species changing simultaneously throughout, 322.

Wrens, nest of, 243.

Youatt, Mr.:  on selection, 31. on sub-breeds of sheep, 36. on rudimentary horns in young cattle, 454.

Zebra, stripes on, 163.

THE END.