Strix grallaria, ii. [302].

Strix passerina, ii. [154].

"Strupp-Taube," i. 155.

Struthers, Mr., osteology of the feet in solid-hoofed pigs, i. 75;

on polydactylism, ii. [13]-[14].

Sturm, prepotency of transmission of characters in sheep and cattle, ii. [66];

absorption of the minority in crossed races, ii. [88];

correlation of twisted horns and curled wool in sheep, ii. [326].

Sub-species, wild, of Columba livia and other pigeons, i. 204.

Succession, geological, of organisms, i. 11.