Observations on phototropic responses of the larvae of Bugula neritina and of B. flabellata in the presence of stimulating and anaesthetic agents indicate that the light reactions of these organisms may have a diagnostic value for predicting acceleration or retardation of the rate of metamorphosis. Experiments on B. neritina were conducted at the Bureau of Fisheries, Beaufort, North Carolina; those on B. f labellata, and less extensive observations on B. turrita, were made at the Marine Biological Laboratory, Woods Hole, Massachusetts
