tides. Considerable research on these animals is now under way. This symposium will bring together for the first time almost ali of the investigators currently active in the field, including several from abroad. Varying degrees of terrestriality have been achieved by three major groups of crustaceans. In the first session of the symposium, speakers will describe the progress made by these three groups. With the groundwork for the symposium presented, the remaining sessions of the symposium will then consider in more detail various aspects of the physiology, ecology, and behavior of terrestrial crustaceans. The papers will deal mainly with isopods and decapods, on which most experimental research has been and is being done. A feature of each session will be a general discussion at its conclusion. F, John Vernberg, E. B. Edney, Desmond E. Hurley, Dorothy E. Bliss, E. L. Bousfield, and G. W. Wharton. Frederick A. Kalber, John D. Costlow, Jr.. C. G. Bookhout, Paul P. Rudy, D. Eugene Copeland, Linda Habas Mantel, and Betty J. Wall. W. B. Vernberg, Don Curtis Miller, James R. Redmond, Leonard Stutman, Marilyn Dolliver, John Mark Dean, John M, Augenfeld, and Oscar H, Paris. Dorothy M. Skinner, Wolfgang Wieser, Roy Hartenstein, Charies A. Gifford, John D. O'Connor, Lawrence I. Gilbert, and Edward J. de Villez. E. B. Edney, Michael R. Warburg, K. Ranga Rao, Franklin H. Barnwell, William Herrnkind, E. B. Edney, and Milton Nathanson. Helen Ghiradella, James Cronshaw, James Case, Howard O. Wright, Michael Salmon, Samuel Atsaides, Hermann Schdéne, June F. Harrigan, Brian A. Hazlett, and Howard 8, Hodgson. Web-Building Spiders (29-30 Dec.) Arranged by Peter N. Witt (North Carolina Department of Mental Health, Raleigh). Spider Silk and Spinning. Central Nervous System Anatomy and Function: The Vibration Receptor. Poisons, Traps, Prey-Catching Behavior. Webs and Web-Building. The geometric orb web which certain species of spiders build every morning has been investigated as a record of the animal’s behavior. Complexity as well as uniformity of shape, species specificity and changing of the pattern with age, disturbances of geometry through bodily injury or through changes in body chemistry by drugs, have offered a special opportunity to analyze changes in behavior. The symposium constitutes the first meeting of scientists with diverse backgrounds whose work has contributed to the understanding of web-building. Silk synthesis, thread ex- trusion, and their regulation are first discussed from the biophysical, chemical, and anatomical angle. The central nervous system of spiders, its structure as well as function, mathematical and computer approach to the elucidation of web geometry are explored. The discussion should lead to better understanding of spiders and to the formulation of general rules of body-behavior interaction in animals. Peter N. Witt, David B. Peakail, R. M. Langer, W. B. Eberhard, V. L. Friedrich, Ronald Wilson, A. Shulov, and Gershon Levi. Charles F. Reed, K. Sasira Babu, Charles Walcott, and Louis Leguelte. Hans M. Peters, John McCrone, Wolfgang Buecherl, Michael Robinson, Harro Buchili, Jonathan Reiskind, and Bertrand Krafft. William Eberhard and Samuel Bays. Functional Morphology of the Vertebrate Heart (28 Dec.) One of the most important functions of the vertebrate circulatory system, and hence ofthe heart, is the distribution of oxygenated blood to all parts of the body. Thus any changes in the respiratory apparatus must be reflected in the circulatory system. In most fishes gills form the main respiratory surface, and the circulation is arranged as a single circuit with the blood passing from the heart to the gills to the body to the heart. However, in lungfish and tetrapods, lungs largely or entirely replace the gills and a new arrangement must be developed. In birds and mammals a complete two-circuit system—heart to lungs to heart to body to heart-—is achieved, but in lungfish, amphibians, and reptiles various “compromises” are found. In this symposium the various problems in delivering oxy- genated blood to all parts of the body and in keeping it separated from the non-oxygenated blood and the ways in which different vertebrates have met them will be discussed. Thomas S, Parsons, David Randall, David Hanson, Kjell Johansen, Fred N. White, and Ursula Rowlatt. Radiation and Behavior (29 Dec.) Arranged by Howard Vogel, Jr. (University of Tennessee). Donald J. Kimeldorf, James C. Smith, Gary S,. Shaber, Robert L. Brent, James A. Rumsey, Gail Newingham, John R. Tester, D. B. Siniff, Orrin J. Rongstad, Ernest Furchgott, and Sylvan J. Kaplan. Primary Productivity and Mineral Cycling in Natural Ecosystems (27 Dec.) Arranged by Harold E. Young (University of Maine). There is a growing awareness by mankind that the most critical problems facing the world are population growth, 2 percent per year, and rapid deterioration of man’s environment. The solutions to these problems and their corollaries challenge the efforts of scientists and non- is explored as an organ in which incoming signals from various receptors are processed, and where the leg movements are regulated for positioning of the thread. Webs are only a special form of traps, and other prey-catching tools of spiders, including their poisons, form the topic of scientists alike. To solve these problems, research must first be conducted by scientists within a number of separate disciplines. The results must then be integrated into a series of action programs with little time before such pro- orb construction, its plasticity as well as rigidity, and the The environment is of concern to manyscientific dis- a third session. In the final session, the time sequence of 1352 grams must go imto effect. SCIENCE, VOL. 158 fist