Fig. 1. Planula migration. Images of a single planula larva migrating toward light were captured at the rate of 1 image per 30 s and superimposed to create one figure. Note that the specimen oriented the blunt end of its spindle-shaped body toward light and that contraction and relaxation of tissue along the body axis accompanied migration. The specimen shown was migrating faster (1.2 mm min^-1) than average (0.3 mm min^-1, see Fig. 5C) thus facilitating visualization of changes in shape and position during migration. Scale bar, 1 mm.