Observations on the Respiration of Australorbis Glabratus and Some Other Aquatic Snails

A study of the rate of oxygen consumption of nine species of pulmonate snails and eight species of operculate snails showed that the pulmonates had consistently a higher metabolic level than the operculates if specimens of equal weight were compared. 2. In both groups, the intensity of oxygen consumption decreased with increasing size of the specimens if referred to unit weight, but remained about constant if referred to relative surface. The oxygen/surface relationship held true both in inter- and intra-specific comparisons and was especially close in the latter case. 3. Australorbis glabratus was able to maintain an approximately steady rate of oxygen consumption over a wide range of oxygen tensions. 4. The oxygen consumption of Australorbis glabratus increased with rising temperature in the range of 0.3 to 37° C., but 41° C. was lethal. The temperature relationship calculated according to Arrhenius' equation gave within the tolerated temperature range a straight line. A good fit to Krogh's normal curve was also obtained and an extension of this curve to a higher temperature range than used by Krogh is presented. 5. The intensity of the oxygen consumption of four species of pulmonate snails sank during protracted starvation first rapidly and later on slowly without reaching a steady level. The respiratory quotient of Australorbis glabratus sank during inanition to very low levels and rose only slowly after feeding was begun again. 6. The possible implications of some of the studied factors on snail control measures are briefly discussed.