Colon, 68. Dead-leaf butterfly (illus.), 211. Colonial jelly-fishes, 45; Protozoa, Death, 103. Cottony cushion scale (illus.), 142. Diodon hystrix (illus.), 134. with sea-anemone (illus.), 177. Cricket, auditory organ of (illus.), Cricket, mole (illus.), 146. Crinoid (illus.), 305. Crop, 71. Crowd of animals, 114. Crustaceans, adults and larvæ Dismal Swamp fish (illus.), 282. Cteniza californica, nest of (illus.), Division of labor, 22, 168. 261. Cyanocitta cristata (illus.), 138. Cypselurus (illus.), 131. Dog, pointer (illus.), 256. Duration of life, 101. Earthworm, alimentary canal of | Fish, egg of (illus.), 79; embry- (illus.), 71. Ectoblast, 82. Ectoderm, 33. Egg case of Californian barn-door Egg cell, 21, 56. Egg, fertilized, 35; of bird (illus.), Embryonic development, 80; of onic stages of (illus.), 87; -louse Fishes, man-of-war (illus.), 175; Flatworm, alimentary canal of Flounder, development of (illus.), Form, primitive, 20. Gapes, worm which causes, 60. Eye of dragon-fly (illus.), 239; of Gastrula, 82. jelly-fish (illus.), 238. Gemmule, 35. Generalization, 66. Fauna, 296; bassalian, 305; littoral, Generation, spontaneous, 51. 306; pelagic, 304. 244. Generations, alternation of, 51. Gerrhonotus scincicauda (illus.), 204. Giraffe (illus.), 126. Globigerina-ooze, 18. Globigerinæ, 16. Gonium, 25-30. Gonium pectorale (illus.), 25. Hydra vulgans (illus.), 38. Grasshopper, auditory organ of Icerya and Vedalia, 121. Icerya purchasi (illus.), 142. Ileum, 68. Individual, 31. Gregarina polymorpha (illus.), 14. | Indo-African realm, 301. (illus.), 234. Green-leaf insect (illus.), 210. Gregarina, 13, 182. Habitat, relation of species of, 283. | Instincts, altruistic, 243; classifi- Habits, domestic, 257. Habits, nest-making, of birds, 264; Hermit-crab, with the sea-anemone Hibernation, 103. Hiving honey-bees (illus.), 154. Honey-bee (illus.), 150; adult and Host, relation of parasite to, 179. (illus.), 265, 266. cation of, 243; concerned with Intestine, 68. Invertebrates, nest-making habits Irritability, 8, 240. Island, coral (illus.), 44. Jack-rabbits, showing variation Jay, Canada (illus.), 138. of Jelly-fish, eye of (illus.), 238. Kallima (illus.), 211. nest of rufus Kangaroo (illus.), 139. Katydid, egg of (illus.), 79. Lady-fish, metamorphosis of (illus.), | Marks, recognition, 22, 129, 223. 98. Larva, 92; of the mosquito, 93; Lepas, adult and larva (illus.), 195; metamorphosis of (illus.), 101. Lernæocera (illus.), 188. Life, communal, 168; duration of, Light, influence of, on animals, 237. Lipeureus densus (illus.), 188. Littoral fauna, 306. Lizard, alligator (illus.), 204. Lizzia koellikeri, eye of (illus.), 238. Medusæ, 41. Melanerpes formicivorus bairdii, Metamorphosis, 90; of Albula vul- 99. Metridium dianthus (illus.), 43. Migration of lemming, 118; of lo- Locust, post-embryonic develop- Mind, 255. ment of (illus.), 91. Mining-bee, nest of (illus.), 160. Islands | Molt, 91. Louse, sucking (illus.), 188. Macropus rufus, 139. Mad Tom (illus.), 132. Male, 57. Mammals, care of young of, 268. Manatee (illus.), 277. Monarch butterfly (illus.), 219; Mosquito, auditor organ of (illus.), Man-of-war, Portuguese (illus.), Moth, cankerworm (illus.), 59. 175. Mantis (illus.), 127. Many-celled animal, 2. Marine Protozoa, 15. Mountains as barriers to distribu- tion, 293. Mouth parts of mosquito (illus.), 127. Mouse-fish in gulf-weed (illus), 208. Mutual aid, 163. 234; of grasshopper (illus.), 234; Ornithotomous sutorius, nest of, Osprey Falls (illus.), 285. Ox, alimentary canal of (illus.) 67. Pagurus (illus.), 176. Narcine brasiliensis (illus.), 135. Nokee (illus.), 132. Nomeus gronovii (illus.), 175. Pandorina sp. (illus.), 26. (illus.), 227. Paramecium aurelia (illus.), 10. 11. Parasite of caterpillar (illus.), 190; Parasites, simple structure of, 181. Obelia, alimentary sac of (illus.), | Parthenogenesis, 60. 69. Esophagus, 67. Omasum, 67. One-celled animals, 2. Patagonian realm, 302. Pediculus (illus.), 188. Pelagic fauna, 304. Pelican, brown (illus.), 125. Organ, 63; auditory, of cray-fish | Peneus, adult and larva (illus.), |