ABSTRACT
In the first paper of this series (Howes and Wells, 1934), we showed that active specimens of the edible snail (Helix pomatia) continually undergo considerable fluctuations in weight, due to changes in their water content, even in environments which do not greatly vary in physical properties. The following experiments were performed in order to find out whether similar phenomena occur in slugs. Most of the experiments were done on Arion ater, but specimens of Limax flavus were also studied. The results obtained on the two species will be described separately and then discussed together.
Since the above was written, one of us (N. H. H.) has built an apparatus in which the weight of Helix pomatia is continuously recorded on a drum and drinking and eating are also recorded. The animal is only disturbed once a week, and not daily as in the experiments above described. Preliminary results show that the animals undergo, in ordinary room air, weight cycles having a period of several days, and that our curves obtained by daily weighing indicate fairly exactly the true weight curves of the snails. Slugs have not yet been studied on the apparatus.
