Simple Invertebrate

the Hexactinellida (glass sponges), the Demospongia, and the Calcarea (calcareous sponges).

A phylum of more or less radially symmetrical invertebrate animals that lack a true body cavity.

Is a group commonly referred to as segmented worms.

Are a life stage for most animals of the class Hydrozoa.

A free-swimming marine coelenterate with a jellylike bell- or saucer-shaped body that is typically transparent and has stinging tentacles around the edge.

A group of soft-bodied, usually much flattened invertebrates.

Roundworms (nematodes) are bilaterally symmetrical, worm-like organisms that are surrounded by a strong, flexible non cellular layer called a cuticle.

Are small parasites that can live in the colon and rectum.

A parasitic flatworm, the adult of which lives in the intestine of humans and other vertebrates.

An aquatic mollusk that has a compressed body enclosed within a hinged shell, such as oysters, clams, mussels, and scallops.

A mollusk of the large class Gastropoda, such as a snail, slug, or whelk.

Have a body cavity called a coelom with a complete lining called peritoneum derived from mesoderm (one of the three primary tissue layers).

An invertebrate lacking a coelom especially : one belonging to the group comprising the flatworms and nemerteans and characterized by bilateral symmetry and a digestive cavity that is the only internal cavity.

Symmetry around a central axis, as in a starfish or a tulip flower.

Lack of equality or equivalence between parts or aspects of something; lack of symmetry.

The property of being divisible into symmetrical halves on either side of a unique plane.

A slender flexible limb or appendage in an animal, especially around the mouth of an invertebrate, used for grasping, moving about, or bearing sense organs.

Is an explosive cell containing one giant secretory organelle or cnida (plural cnidae) that defines the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.).

The outermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the epidermis and nerve tissue.

The innermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the lining of the gut and associated structures.

A female reproductive organ in which ova or eggs are produced, present in humans and other vertebrates as a pair.

The male sex gland, located behind the penis in a pouch of skin called the scrotum.