Fig. 4. Adults exhibit LTM but juveniles do not. (A) Adult (N=75) snails subjected to the LTM training procedure exhibited LTM when tested 24 h after the last training session (MT). That is, the criteria for LTM (the number of attempted openings in MT was significantly less than in session 1 but was not significantly greater than in session 2) were met. (B) Juvenile (N=75) snails trained and tested in the same manner as the adults in A did not meet the criteria necessary for LTM.