1903. Instinct and Intelligence in the Animal Kingdom. A Critical Contribution to Modern Animal Psychology. pp. 171. St. Louis, Mo. From the second and enlarged German edition. 1905. Comparative Studies in the Psychology of Ants and of Higher Animals. pp. 200. St. Louis, Mo. Translated from the revised and enlarged second German edition. WATSON, J. B. 1908. The Behavior of Noddy and Sooty Terns. Pub. 103, Carnegie Inst. pp. 187-255. An excellent account of bird behavior in colonial species. WHEELER, W. M. 1903. Ethological Observations on an American Ant (Leptothorax Emersoni Wheeler). Jour. für Psychol. und Neurol., Bd. II, pp. (1-31). 1910. Ants, their Structure, Development and Behavior. pp. 663. New York. The most useful single work on ants, ant behavior, slaves, commensals, etc.; a very important work. Extensive references. WHITMAN, C. O. 1899. Animal Behavior. Biol. Lectures, Marine Biol. Lab., Wood’s Holl, 1898, pp. 285-338. Behavior of leech, Necturus, birds, etc. WICKHAM, H. F. 1899. The Habits of American Cicindelidæ. Proc. Davenport Acad. Sci., Vol. VII, pp. 206-228. YERKES, R. M. 1904. Space Perception of Tortoises. Jour. Comp. Neurol. and Psychol., Vol. XIV, pp. 17-26. YOAKUM, C. S. 1909. Some Experiments upon the Behavior of Squirrels. Jour. Comp. Neurol. and Psychol., Vol. XIX, pp. 541-568. IX. THE CONTINUOUS PROCESS OF ADJUSTMENT BETWEEN THE ENVIRONMENT AND THE ANIMAL, WITH SPECIAL REFERENCE TO OTHER ORGANISMS THE DYNAMIC OR PROCESS RELATION OF ANIMAL ASSOCIATIONS AND AGGREGATIONS 1. The Struggle for Existence. 2. The Dynamic Relations of Aggregations and Associations, with Special Reference to Animal Associations. _a._ The Relation of Animals to Pollination and to Plant Galls. _b._ Subterranean and Cave Associations. _c._ Selected References on Aggregations and Associations. “Nothing is easier than to admit in words the truth of the universal struggle for life, or more difficult--at least I have found it so--than constantly to bear this conclusion in mind. Yet unless it be thoroughly engrained in the mind, the whole economy of nature, with every fact on distribution, rarity, abundance, extinction, and variation, will be dimly seen or quite misunderstood.”--DARWIN. “Every reflective biologist must know that no living being is self-sufficient, or would be what it is, or be at all, if it were not part of the natural world, although no truth is easier to lose sight of. Living things are real things, ... but their reality is in their interrelations with the rest of nature, and not in themselves.”--W. K. BROOKS. (1906.) _1. The Struggle for Existence_ DARWIN, CHAS. 1876. Struggle for Existence. pp. 43-61. In On the Origin of Species, 6th ed. New York. (See Figures 2 and 3.) BROOKS, W. K. 1893. Salpa in its Relation to the Evolution of Life. Studies Biol. Lab., Johns Hopkins Univ., Vol. V, pp. 129-211. See particularly pp. 129-170.