Phylum Mollusca - Mollusks - includes snails, slugs, clams, scallops ...

Have highly developed nervous systemsRapid responses result from giant nerve fibers attached tomantleEyes are elaborate with retina similar to that in vertebratesExhibit complex behaviors and high level of intelligenceTake water into mantle and expel it through siphon for propulsionChange direction of movement with siphonMay eject dark fluid to confuse predatorsMost have closedcirculatory system thatprovides more efficientcirculationSexes are separateSpecialized tentacle in male transmits spermatophore to femaleEggs fertilized as they leave the oviductextensive parental care in some