INDEX 



Italicized numbers indicate illustrations. 



Aardvark, 508 



Abiogenesis, 408 



Abomasum, 288 



Absorption, by root hairs, 244-245 



Absorption spectra of green plants, 257 



Acanthocephala, 87 



Achatinella, 523 



Acid-base balance, 310 



Adaptability, to new conditions, 40 



Adaptations, 486-493 



biological, 492-493 



embryological, 487-488 



for food getting in animals, 51-52 



for food getting in birds, 52 



for life in air, 23-24 



for life in water, 21-22 



for life on land, 24-25 



for protection of young, 47 



for seed dispersal, 272 



genetical, 489-490 



in desert plants, 36, 37 



in worker bees, 207-208 



organic, 486 



physical, 490-492 



physiological, 488-489 



psychological, 489 



structural, 486-^57 

 Adaptiveness, definition of, 127 

 Addison, 391 

 Addison's disease, 393 

 Adenoids, 287 

 Adjustor neuron, 341 

 Adrenals, 392-394 

 Adrenin, 393, 394 

 Adrenotropic hormone, 401 

 Aedes mosquito, 618, 619 

 Aepyornithiformes, 113 

 Aerating devices, in plant, 17 

 Aestivation, 10 

 Afferent fibers, in bee, 211 



in earthworm, 194, 195 

 Agassiz, 502 

 Ages, cultural, 547 

 Agglutination test for typhoid, 627 

 Agglutinins, 626 

 Agnatha, 105 

 Agouti, 508 

 Agriculture, 550 

 Ainu aborigines, 561 

 Air sacs, 315 



function of, 210 



in insects, 210 



Alare, 563 

 Albatross, 113, 523 

 Algae, 69, 71, 169-172 

 Alimentary canal, 282 

 Allantois, 426, 427, 487, 501 

 Alligators, 103, HI 

 Alpine races, 561 

 Alternation of generations, 414 



angiosperms, 176-178 



hydroids, 186 



plants, 174-176, 175 

 Alveolus, 317 

 Ambulacral fluid, 335 

 Ambulacral grooves, 336 

 Ameba, 77, 103, 328, 342 



food of, 155 



mitotic division in, 155 



structure of, 154-156 

 Ameba proteus, 154 

 Amebic dysentery, 620 

 American Ornithologists' Union, 600 

 American passenger pigeon, 599 

 Amino acids, definition of, 131 

 Ammonites, 513 

 Amnion, 424, 425, 4^7, 487, 497 

 Amniotic fluid, 426 

 Amphibia, 103, 109, 497, 501, 513, 



533 

 Amphimixis, 161, 162, 163 

 Amphineura, 97 

 Amphioxus, 105, 329 

 Amphioxus ova, 418 

 Ampulla, echinoderms, 336 



mammalian ear, 361 

 Amylopsin, 295 

 Anabolism, 126 

 Analogy, 67 



Anal spot of Paramecium, 159 

 Anaphase, 142, 143 

 Anatomy, comparative, 496-497 



human, 496 

 Ancyrocephalus, 223 

 Angiospermae, 75 

 Angiosperms, alternation of generation 



in, 176-178 

 Animal breeding, methods of, 571-573 

 Animal cell, typical, 130 

 Animals 



as food, 575 



economic value of, 576-578 



harm done by, 582-586 



in fresh water, 153-154 



