INDEX 



861 



Homologous organs, 727 

 Homologous structures, 424 

 Homozygous, 654 

 Honey-ants, 347 

 Honeybee, 317, 347 

 Honey-stomach, 318 

 Hoof, 498, 506 

 Hooke, Robert, 10 

 Hookworm, 807 

 Hopeful monster. 706 

 Hoplocarida, 836 

 Hormones, 111, 328, 605 



arthopod, 328 



effects of, 609 



purification of. 607 

 Horned toad, 459 

 Horns, 504 



Horny scales. 453, 471, 505 

 Horses, 498 



Human bodv. composition of, 21 

 Human ecology, 829 

 Human inheritance, 691 

 Hinncrus, 401 , 512 

 Humidity, 340 

 Hummingbird, 482, 483 

 Hummingl)ird moth, 340 

 Hunter, John, 11 

 Hutton, James, 697 

 Hyaluronidase, 571 

 Hybrid vigor, 681 



Hybridization, origin of species by, 709 

 Hydra, 198 



reproduction in, 199 

 Hydrocortisone, 618 

 Hydroides, 281, 834 

 Hydrolysis. 81 

 Hydrozoa, 189, 190, 833 

 Hyla, 451, 840 

 Hymen, 570 

 Hymenoptera, 316, 837 

 Hyoid. 510 

 Hyoid apparatus, 398 

 Hyoid arch, 432, 508 

 Hyoid bone, 511 

 Hyomandibular. 435 

 Hyperglycemia, 616 

 Hypersecretion, 606 

 Hypersensitivity, 619 

 Hypertonic solution. 52 

 Hypophyseal sac. 429 

 Hypophysis, 620 

 Hyposecretion, 606 



Hypothalamus, 428, 597, 601. 620, 627 

 Hypothesis, 3 

 Hypotonic solution, 53 

 Hypotrichs, 164, 832 

 Hyracoidea, 500, 842 

 Hyracotherium, 708 

 Hyrax, 842 



I 



Ichthyornis, 481, 841 



Ichthyosaurs, 456, 840 



Identical twins, 115, 646, 692 



Ileocaecal valve, 521 



Ileum, 521 



lUum, 401, 512 



Immobilization, 342 



Immunitv. 542 



Implantation of fertilized egg, 571 



Impulse, initiation of, 587 



Inarticulata, 838 



Inborn errors of metabolism, 688 



Inbreeding, 681 



Incisors, 487, 516 



Incurrent pores, 172 



Incurrent siphon, 252, 386 



Incus, 466, 511, 583 



Inductor tissues, 136 



Infectious diseases. 543 



Infundibulum. 416, 620 



Inheritance of acquired characters, 697 



Inhibition, 587 



Ink sac, 263 



Inner cell mass. 638 



Innervation of arthropod muscles, 332 



Inorganic compounds in cell, 23 



Insect development, control of. Ill 



Insect pests, control of, 824 



Insecta, 306 



classification of, 313 

 Insectivores, 492, 842 

 Insects, flight mechanism in, 334 

 metamorphosis in. 314 

 social mechanisms in, 344 

 vision in. 336 

 Insertion. 401 

 Inspiration, 533 

 Insulin, 28, 615, 616 

 Integrated centers. 419 

 Integration, 1 1 1 

 nervous, 574 



Integument, 395, 502 



Interactions between species, 763 



Intercerebral gland, 330 



Intercostal muscles, 534 



Intermedin, 419, 622 



Internal carotid, 408 



Internal gill. 420 



Internal gill slit. 430 



Internal nares, 510, 532 



Internuncial neurons, 588 



Interoceptors, 108 



Intersexes, 661 



Intestinal glands, 521 



Intestine, 430, 521 

 cross section of, 521 



Intracellular differentiation, 149 



