THE BURGESS SHALE OF COLLOIDS. Like the rocky hillside in the Canadian Rockies which harbored a trove of animal phyla not seen before (see SJ Gould's book "Wonderful Life"), a range of new colloid structures has been created by scientists at Brandeis in suspensions of tiny rod-like (viruses) and sphere-like (e.g., polystyrene balls) particles. Demonstrating again the principle that the inexorable increase in entropy in the universe needn't preclude localized order (i.e., order in part of a system can result if this creates the opportunity--in the form of a greater free volume--for greater disorder in the rest of the system), the Brandeis experiment has turned up a variety of never-before-seen rod-ball structures in which the main architectural force is not inter-particle interactions but rather entropy-driven phase transitions. (For example, in one odd structure, planes of stacked rods were separated by sheets of balls, with extra columns of balls appearing at regular intervals--- see figure at Physics News Graphics). It's as if in a sea of otherwise non-interacting billiard balls and cues the influence of entropy had caused the particles to acquire an effective size-and- shape-dependent attractive potential which obliges the particles to take up their novel configurations. The appearance of this spontaneous self-assembled order would seem to be important in a number of colloid systems, such as the segregation of DNA molecules inside prokaryotic cells (cells without a distinct nucleus). (Nature, 28 May 1998; contact Seth Fraden, seth@smectic.elsie.brandeis.edu.)