Homologous parts, correlated variability of, ii. [322]-[331], [354]-[355];

fusion of, ii. [393];

affinity of, ii. [339]-[342].

Hoofs, correlated with hair in variation, ii. [325].

Hook-billed duck, skull figured, i. 282.

Hooker, Dr. J. D., forked shoulder-stripe in Syrian asses, i. 63;

voice of the cock in Sikkim, i. 259;

use of Arum-roots as food, i. 307;

native useful plants of Australia, i. 311;

wild walnut of the Himalayas, i. 356;