Birds, _ancient_, 123, 153; with jointed tails, 130; with teeth, 130; arose not direct from reptiles but from a common ancient stock, 131; avoiding winter by migration, 348; climbing, 162; dangers of land, 154–156; darting, 167; feet of perching, 155; ground, 156; _a group of wading_, 149; growth of feathers of, 133; habits of scratching, 156; linked in structure to reptiles, 129; love-time of the, 124; lungs of, 135; migrations of, 142, 151, 155, 177; mound-building, 158; nest-building, 170; origin of, 337; perching, 168; of prey, 174; range of, 136; rise from ground to perching, 159; running, 136–140; sea, 142; singing, 168; songless, 169; structure of water-, 141; third eyelid of, 136; throat of singing, 169; wading, 148; warmer-blooded than man, 135; wingless, 139. Bisons, protecting a young one, 269; the only ruminants of America, 274. Blennies, walking-fish, 57. _Blue shark_, _Carcharias glaucus_, 29. _Boa constrictor of America_, 115; manner of seizing and devouring prey, 117. Boar, defences of the wild, 260. “Bombay Duck” a phosphorescent fish, 48; _figured_, _see frontispiece_. Bone at tip of mole’s nose, 224. Bonito, a fish without air-bladder, 53. Bony fish, agility of, 44; or modern fish, 27; _early forms of_, 43; origin of, 45; rise and spread of, 43; structure of, 45. Bony pike of North America, 33. Box-tortoises closing their shell, 101. Brazil, monkeys of, 246. Breast-bone, flat in running birds, 136; keeled of flying birds, 124. Breathing apparatus of birds, 135; of bony fish, 45; of frog, 75, 76; of lamprey, 17; of lancelet, 12; of marsupials, 192; of minnow, 23; of mud-fish, 34; of seals, 308; of shark, 30; of the snake, 113; of sturgeon, 32; of tadpole, 73, 74; of tortoise, 95; of whales, 321. British Museums, specimens in, 32, 34. _Brush-turkeys and their mounds_, 158. _Buffalo cow defending her calf_, 274. Buzzard killing a viper, 120. Cæcilians, nearest type to Labyrinthodonts, 84; worm-like amphibians, 82. Calf-fish or amia, 33. California, sea-otters of, 301. Californian gray whale in ice, 330; killed by a shoal of grampuses, 325. _Camel_, 270; the only ruminant with upper front teeth, 270. Capybaras of South America, 215. _Carapace of tortoise_, 98. Carnivora, or flesh-feeders, 257, 259; ancestors of the, 213; the smaller, 280. Carnivorous marsupials, 196. Carp family, 65. _Cartilaginous fish_, 31–42. Cassowary of New Guinea, 139. Cat-fish, 65. Cat less tamable than dog, 287. Cave-lion in England, 343. _Celebes, double-tusked hog of_, 262. _Ceratodus or “Barramunda,”_ 34; a descendant of ancient fish, 39. Chalk Period, extinction of reptiles in the, 211.