Index 879 



Homonomous, 836 

 Homospory, 136, 192-196 

 Homozygous, 682, 685 

 Honeybee, 398-408, 399*-404,* 571 

 Hooke, Robert, 28, 37, 802 

 Hooks, 377, 377,* 379, 400, 538* 

 Hookworm, 295, 296,* 298, 539, 785 

 Hoppers {see Insects) 

 Hormogonia, 113,* 154, 836 

 Hormones, animal, 506, 510-513, 767- 

 772 

 plant, 239-242, 767-772 



Horse, origin and development, 725,* 

 726* 



Horsetail (scouring rush), 100-112, 137, 



137,* 191, 194, 195, 256 

 Host, 664 

 How science solves problems, 804, 805 



to study, 19 

 Human muscles, 467-472, 467,* 468* 



resources, 797 

 Huxley, 803 

 Hybrid vigor, 705 

 Hybridization, 684 



of corn, 704,* 705, 706 

 Hydatid (tapeworm larvae), 537, 788 

 Hydra, 286, 286,* 287, 289 

 Hydranth, 285* 

 Hydrogen, 79,* 81,* 83,* 169 

 Hydrogen-ion concentration, 631, 751, 

 836 



Hydroid, 289, 290 

 Hydrolysis, 92 

 Hydrophyte, 206, 653 

 Hydroponics, 775, 776 

 Hydrorhiza, 285* 

 Hydrostatic, 836 

 Hydrotropism, 243 

 Hydroxyl, 751, 836 

 Hydrozoa, 285,* 289, 289* 

 Hymenium, 127,* 128,* 176 

 Hymenoptera, 398-408 {see also In- 

 sects) 



Hyoid bone, 423, 424, 466, 469* 

 Hypersensitiveness, 520, 772, 773 

 Hypertonic, 753 

 Hypertrophy, 837 



Hypha, 124, 124,* 126, 126,* 127,* 

 167, 173-176, 179 



Hypocotyl, 144,* 147,* 202, 204, 210, 

 213 



Hypodermis, 837 

 Hypopharynx, 410, 411* 

 Hypophysin {see Endocrine glands) 

 Hypophysis, 495,* 496,* 507 

 Hypostome, 286* 

 Hypotheses, 22 

 Hypotonic, 754 



Ichneumon, 572* {see also Insects; 



Hymenoptera) 

 Ileum, 427,* 470,* 471, 475* 

 Ihum bone, 423, 425 

 Im.munity, 518-522 

 Impressions (imprints), 605, 611 

 Improvement by heredity, 704,* 705, 



706 

 Impulse in nerve, 498-502, 489* 

 Inanimate things, 99-103 

 Inbreeding, 703, 705, 706 

 Incomplete dominance, 690-692 {see 



also Heredity) 

 Incrustation, 610 

 Incus bone, 466, 498,* 505 

 Indeterminate variations, 724 

 Indian pipe, 671 



Indirect cell division (mitosis), 62-72 

 Individuality, 97 

 Indusium, 198 

 Industrial plants, 257-271 

 Infusoria, 276, 278*-280,* 349, 354, 

 531,* 532,* 534 {see also 

 Protozoa) 

 Ingestion, 344 {see also specific organ- 

 isms) 

 Ink, 315,* 542, 547 

 Inner cell mass, 451,* 452 

 Innominate vein, 488,* 490,* 741* 

 Inorganic salts, 89 

 Insanity, heredity of, 717* 

 Insectivorous plants, 658, 668, 668* 

 Insects, 319, 393-408 {see also Grass- 

 hopper; Honeybee; etc.) 

 classification and identification, 409- 



420 

 economic importance, 550-572 

 metamorphosis, 410, 414-418 

 mouth parts, 409, 410,* 411,* 414- 



418 

 orders of: 



Anoplura (lice), 415, 553 



Aptera (Collembola; Thysanura), 



414, 450 

 Coleoptera (beetles), 417, 563 

 Collembola, 414, 550 

 Corrodentia, 416, 557 

 Dermaptera, 417, 561 

 Diptera, 418, 568 

 Ephemerida (Ephemeroptera), 



414, 550 

 Hemiptera, 416, 557 

 Homoptera, 416, 558 

 Hymenoptera, 418, 571 

 Isoptera, 415, 555 

 Lepidoptera, 418, 565 

 Mallophaga, 415, 551 

 Mecoptera, 417, 565 



