Preface to Class of Gastropoda

Gastropoda
Photo: Ralph Body 		Literal meaning: Stomach-footed

Common names: Snail, Slug, Limpet, Whelk
Gastropoda Shell: A calcareous, coiled or cup-shaped shell that begin to form within the first few hours of embryonic development is typical of this class.
  • A few species have internal shells while the Nudibranchs have no shell at all.
  • Shells may have spines or other ornamentation.
  • Some have a notch or canal on the lip of the shell thru which a siphon extends.

  • The size of the shell is variable ranging from about 1mm to over 609 mm in length and 456 mm in width

    Animal: The animal has a head which is fused to a flattened, disk shaped muscular foot, and     mantle.
  • Well-developed sensory organs include eyes and tentacles.
  • A radula is present and is sometimes used as a guide to classification.
  • Gill also called ctenidia, the heart and nervous system are also used for this purpose.
  • A unique characteristic of this class is torsion. The embryo is bilateral, but very early in the development the larva twists and the larva becomes asymmetrical and spirally coiled. As a result the gills, anus and kidney exit-tubes are anterior rather than posterior.
  • Fertilization varies among groups being internal in some and external in others.
  • Development of the embryo is equally diverse.

    Habitat: Gastropods represent the largest and most successful group of all mollusks.

  • Gastropods have a world-wide distribution living on land as well as in fresh and marine waters.
  • About 60% of the living species are marine while the remainder live either on land or in fresh water.

    Food: As a result of having the ability to occupy numerous habitats, gastropods have been able to take advantage of a variety of food sources as either carnivores or herbivores.

  • The size, shape and number of teeth of the radula determine the food source.

    Reference: Class - Gastropoda