INDEX. 



Abdominal pore, 228. 



Acanthometraj, 50. 



Actinophrys, 44, 156. 



Adults, the primordial state of animals, 



106. 



Aerification, 211. 

 Affinity, chemical, 7. 

 inorganic, 7. 

 organic, 7. 

 vital, 7. 

 Agassiz on the systematic position of 



Infusoria, 174. 

 the parasites of Hydra, 174. 

 Vorticellidae and Bryozoa, 



174. 



Albertia, 274. 

 Albumen and yolk of eggs, diverse origin 



of, 35. 



of the egg, 33. 

 Alcohol, composition of, 8. 

 Algae, 134, 155. 

 Alternate generation, 67. 

 Ammocuetes, 125. 

 Ammonia, composition of, 8. 

 Amniotic sac, 306, 309. 

 Amoeba, U. 



organic functions of, 11. 

 Amphioxus, 126, 226. 

 Anchorella, 272, 274. 

 Animal-egg, the, 88. 

 Animal-flower, 57. 

 Animals, the lowest forms known, 15. 



allied by progressive relations, 5. 



false ideas of development of, 6. 



and plants, distinction, 131, 151. 



Animate being, the universe ruled by 



an, 5. 

 Aquiferous circulatory system of Echi- 



noderms, 186, 190. 

 Arachnida, 220. 

 Archeopteryx, 277. 

 Area, vascular, 309. 

 Arrangement, spiral, in corals, 60. 

 Articulata, 119, 214. 



and Protozoa, relations of, 244. 

 compound nature of, 214. 

 and Zoophyta, 246. 

 development of, 298. 



Artificial division, experiments on Pla- 

 naria, 92. 



of Amoeba, 95. 



of Sea-anemones, 89. 



reproduction after, 89. 

 Ascaris, 36. 

 Asteracanthion, 181. 

 Aurelia, 67, 70. 



motions in decomposing cells, 98. 

 Axial plane, of Mollusca, 197. 

 Axolotl, 263. 



B. 



Bacterium, 18, 23, 102. 



Balbiani on eggs of Infusoria, 31. 



Beetle, 221. 



Beings, all living, chemical composition 



of, 6, 8. 



Bell-animalcules, 161. 

 Bilaterality, 128, 267. 



the predominant feature in 



animals, 249. 



early appearance of, in ani- 

 mals, 251. 

 relation of, to reproduction, 



266. 



of Zoophyta, 179. 

 Bipolarity, 267. 

 Birds' eggs, 37. 



Bisymmetry and bilaterality, 185. 

 Blancliard on Planarians, 253. 

 Blood circulation of Echinoderms, 186, 



191. 



Bonellia, 215, 246. 



Brain, experiments on removal of, 127. 

 duplicity of, 127. 

 relative position of, among animals, 



125. 



Branchial aortae of the embryo, 311. 

 fissures of the embryo, 311 

 ganglion, 202. 

 Bryopsis, 139. 

 Bryozoa, 195. 



and Zoophyta, 246. 

 Buccal plates, 190. 

 Budding, individuals arising by, 54. 

 of Bryozoa, 244. 

 Fredericella, 244 . 

 Sea-anemone, 60. 



