ABSTRACT
Activity in slugs has been shown to occur in response to certain temperature changes (Dainton, 1954). In the description of these responses it was stated that light had no effect provided 1 hr. was allowed for light-adaptation. The experiments which led to this conclusion are described in this paper. Light initially stimulates activity in dark-adapted animals, but the response is short-lived, adaptation being complete within an hour. Preliminary observations indicated that activity was also affected by air currents, and responses to this form of stimulation are also described below.
The author is indebted to Dr D. L. Gunn for making the first of these preliminary experiments in the aktograph which he used for his work on the diurnal rhythm of activity in the cockroach.
