Index 



709 



Hyla, 596, 599 

 Hylidae, 596 

 Hymen, 261 

 Hymenolepis, 420 

 Hymenoptera, 539 

 Hyoid apparatus, 108, 130 



arch, 56 

 Hyperfunction, 226, 227 

 Hyperparathyroidism, 233 

 Hypodermis, 424 

 Hypofunction, 226, 227 

 Hypohippus, 333 

 Hypolimnion, 662 

 Hypomere, 288 

 Hypoparathyroidism, 232 

 Hypopharynx, 519, 521, 522, 527, 528, 



529, 530 

 Hypophysis (see Pituitary gland) 

 Hyporhamphus, 590 

 Hypostome, 386 

 Hypothalamus, 199, 211, 243 

 Hypothesis, 19 

 Hyracoidea, 630, 639 

 Hyracotherium, 331 



Ichthyomyzon, 571, 575 

 Ichthyophis, 596 

 Ichthyopterygia, 603 

 Ichthyornis, 623 

 Ichthyornithiformes, 623 

 Ichthyosauria, 603, 612, 613 

 Identical twins, 295 

 Idothea, 507 

 Iguana, 607 

 Iguanidae, 607 

 Ileum, 61, 129, 134 

 Iliac artery, 66, 167 



vein, 68, 168 

 Iliolumbar artery, 168 



vein, 168 

 Ilium, 58, 110 

 Impennae, 625 

 Implantation, 242, 261, 285 

 Impulse, nerve, 208-209 

 Inbreeding, 3l6, 317 

 Incisor, 87, 88, 130 

 Incurrent canal, 378 

 Incus, 220, 221, 222 

 Infection, 178, 183, 221, 239 

 Infundibular stalk, 243 

 Infundibulum, 69 

 Infusoria (see Ciliata) 

 Inguinal canal, 255 



hernia, 256 

 Inhibition, 206, 207 

 Iniomi, 590 

 Ink gland, 477, 479 

 Inner cell mass, 285 



Innominate artery, 166 



bone, 110 



vein, 66, 168, 183 

 Inorganic chemistry, 30 

 Insecta, 44, 518-540, 649, 650 



characteristics, 519-521 



classification, 44, 348, 490 



economic relationships, 535-536 



endocrine, 249 



habit variations, 531-535 



muscular system, 114 



orders, 536-540 



reproduction, 253, 254 



respiratory system, 148 



skeletal system, 33, 92, 94 



structural variations, 527-531 

 Insectivora, 628, 630, 633-634 

 Insertion of muscles, 117 

 Insulin, 137, 237, 238, 239, 240, 250 

 Integumentary system, 40, 54-55, 75-91 

 Interaction of factors, 304-306 

 Intercalated disc, 117 

 Interciliary fibril, 368 

 Intercostal arteries, 167 



muscles, 107, 154, 155 



space, 107 



veins, 168 

 Intermediate lobe of pituitary, 72, 243, 



247 

 Intermedin, 247 

 Interoceptor, 212, 213-214 

 Interparietal bone, 102 

 Interphase, 270 

 Interradius, 395 

 Intersexes, 308-309 

 Interstitial cells, of hydra, 388 

 of ovary, 242 

 of testis, 240, 241 

 Intertidal zone, 664, 665 

 Intestinal juice, 138, 139, 140, 141 

 Intestine, 60, 234 



large, 61, 134-135, 139 



small, 61, 134, 135, 138 

 Invertase, 139 

 Invertebrates, 92, 159, 185, 193, 212 



hormones, 249 

 Iodine, 29, 35, 71, 228, 229, 230, 231 

 lodothyroglobulin, 228 

 Ion, 27 



Iris, 206, 216, 217, 219 

 Irish elk, 330 

 Iron, 29, 35, 145, 177 

 Irritability, 24, 192, 360 

 Ischium, 58, 110 

 Ischnochiton, 476 

 Island faunas, 340 



Islets of Langerhans, 72, 237-240, 250 

 Isogamete, 253 

 Isolation, 328, 338-340 

 Isolecithal egg, 283 



