1. Theeffectoftemperatureontheactivityofthefreshwatersnail Pomaceacanaliculata was
investigatedthroughfieldsurveysandlaboratorytrials.
2. Duringwintermostsnailsinthefieldwereinactivebutnotinadeeplethargicstate;the
temperatureatwhichhalfofthesnailswereactivewas13–15 1C.
3. Thetimespentactiveandfeedingincreasedwithtemperaturebetween10and30 1C, exposuretime
being unimportantexceptinfoulwaterat35 1C, whiletimespentcrawlingremainedconstant
above 10 1C.
4. Activitydecreasedabove30 1C butnoheatcomawasobservedwithtemperaturesraisedto36.2 1C.
5. Underfluctuatingtemperatures,therateofchangeinthepercentageofactivesnailsduringcooling
was higherthanduringwarming,whereasthetemperatureatwhichhalfofthesnailswereactive
was lower.