How do gastropods reproduce?

Most terrestrial gastropods are hermaphrodites, meaning that they have both male and female reproductive organs.  This means that these snails and slugs can act as either the male or female when mating.  When it comes to marine gastropods, most species have separate sexes.  Depending on the species there is either external or internal fertilization, although with marine gastropods fertilization is almost exclusively external.  The lifecycle includes egg laying and fertilization, embryonic development, larval stage, and the growth of the gastropod.  Some species practice hibernation or estivation (a period of dormancy during warm, dry weather).