Hydra, i. 374, ii. [293], [359].
Hydrangea, colour of flowers of, influenced by alum, ii. [277].
Hydrocele, ii. [52].
Hydrocephalus, ii. [295].
Hypericum calycinum, ii. [170].
Hypericum crispum, ii. [227], [337].
Hypermetamorphosis, ii. [367].
Hypermetropia, hereditary, ii. [8].
Ichthyopterygia, number of digits in the, ii. [16].
Ilex aquifolium, ii. [19].