BIOL 205 Study Guide - Final Guide: Vas Deferens, Ovotestis, Love Dart
Document Summary
Most marine gastropods exchange gas using ctenidia. Some have secondarily lost ctenidia and have another type of gill called cerata. Terrestrial and some freshwater snails breathe air. The opening to mantle cavity is called pneumostome. Although most gastropods are dioecious, most terrestrial snails and slugs are monoecious. Some marine and all terrestrial gastropods have direct development. Tiny snails hatch from eggs (no free-living larval stage). In some marine gastropods, first larval stage is the trochophore followed by veliger, but in others, embryo passes through trochopore stage before hatching from eggs so the only free-living larval stage is the veliger larva. In some marine gastropods, the veliger larvae are planktotrophic while in others, the(cid:455)"re lecithotrophic. Inject each other with hormone-laden love darts (calcareous/chitinous spicules made by dart sac) (hormones made by mucus gland) (stab it through body wall of mate to inject it into hemolymph). Hormones increase chance of fertilization by affecting contraction of smooth muscle in copulatory canal of mate.
