Published online by Cambridge University Press: 11 June 2012
A survey has been made of the condition of the mantle cavity in populations of Lymnœa (Radix) peregra (Müller) and Physa fontinalis (L.) living in a range of depths and habitats in Loch Lomond. In many populations, including some in relatively shallow water, the mantle cavity remains water-filled throughout life. Where the cavity contains a gas-bubble, micro-gas-analysis (using a modification of Krogh's methods) has revealed that in some cases the gas composition is such that the bubble could be used as a physical gill, while in others such use is unlikely. Other observations on respiratory behaviour of the two species are reported, and growth-changes are noted in the surfaces available for cutaneous respiration. The study is discussed in relation to previous work on the respiration and ecology of freshwater pulmonate snails.
This paper was assisted in publication by a grant from the Carnegie Trust for the Universities of Scotland.