_Sedimentary_: A term applied to rocks which originated as sediments deposited under water. _Serum_: Watery portion of the blood, the plasma. _Somatic Cells_: Vegetative cells not especially set aside by the organism for reproductive purposes, _e.g._, tissue-cells. _Somite_: One of the uniform segments of the longitudinal series into which a metameric organism (such as an earthworm) is partitioned. _Spermatist_: An old term applied to one who held that the animal embryo was produced entirely by the male parent. _Spore_: A single cell, incapable of syngamy, but capable of giving rise to a new individual without the sexual process. _Symbiosis_: The obligatory association of two organisms of different species for mutual benefit. _Synapsis_: Union in pairs of corresponding (homologous) chromosomes of opposite parental origin as a preliminary to their separation in meiosis. _Systematist_: An expert in classification (systematics), _i. e._, a taxonomist. _Taxonomy_: The science of classification. _Tertiary Period_: A geological time-division corresponding to the rock-system that comprises the greater part of the Cenozoic group. It is made up of four series, namely, the Eocene, Oligocene, Miocene, and Pliocene. Its close marks the beginning of the Glacial or Pleistocene epoch. _Tissue_: A layer of uniform cells specialized for the same function. _Tissue Cell_: One of the somatic cells of which a tissue is composed. _Troglodytic_: Resembling the chimpanzee and the gorilla. _Woods Hole_: The seat of the Marine Biological Laboratory. It is a watering-place on the New England coast opposite Martha’s Vineyard. _Zygote_: The synthetic cell formed by the union of two gametes and giving rise by division either to a new multicellular organism, or to a rejuvenated cycle of unicellular forms. INDEX TO AUTHORS Adami, J. G., 57. Aeby, Christoph Theod., 274. Æsop, 246. Alsberg, Moritz, 317. Altman, Richard, 141. Aquinas, St. Thomas, 32, 73, 268, 343. Aristotle, 133, 155, 172, 174, 192, 196, 197, 200, 202, 214, 215, 227, 230. Armstrong, H. E., 190. Arrhénius, Svante, 166, 167, 182, 183, 184. Augustine, St., 32, 73, 74, 75. Bach, Alexis, 145, 146. Bacon, Francis, 86, 87. Bagg, H. J., 266. Balfour, Arthur James, 358. Ballou, W. H., 318. Bardon, L., 330. Bastian, Charlton, 165. Bateson, Wm., 1, 5, 12, 13, 16, 17, 18, 20, 21, 25, 28, 30, 43, 44, 73, 84, 85, 88, 145, 146, 334. Bather, F. A., 3, 40, 76, 77, 86, 87, 90, 91, 92, 93. Baudlisch, Oscar, 148. Baur, E., 88. Beddoe, 333. Bergson, Henri, 262. Bernouilli, Jacques, 248. Bey, Pruner-, 324. Binet, Alfred, 220. Biot, Jean Baptiste, 135. Blackwelder, Eliot, 117.