Data are saved as tab delimited text files (adults_and_egg_clutches.txt, egg_size.txt, offspring_survival_and_size.txt). Data files have the following columns: adults_and_egg_clutches.txt: mat_temp - maternal temperature treatment (15C, 25C) mat_surv - survival of maternal snails (1 = yes, 0 = no) mat_rep - reproduction of maternal snails (1 = yes, 0 = no) eggs - the number of oviposited eggs offspring_temp - offspring temperature treatment (15C, 25C) hatchlings - the number of hatched offspring first_hatching - the first day of hatching after the egg clutch was laid median_hatching - the median hatching day after the egg clutch was laid last_hatching - the last day of hatching after the egg clutch was laid egg_size.txt: mat_temp - maternal temperature treatment (15C, 25C) clutch - egg clutch the offspring originated from size - two-dimensional area of the egg (mm2) offspring_survival_and_size.txt: mat_temp - maternal temperature treatment (15C, 25C) offspring_temp - offspring temperature treatment (15C, 25C) clutch - egg clutch the offspring originated from surv - survival until the end of the experiment (1 = yes, 0 = no) size - shell length at the end of the experiment (mm)