Class Hydrozoa, Scyphozoa, and Anthozoa

Pneumatophore

-the gas-filled float of some colonial Physalia

Hydra (phylum Cnidaria)

. A solitary hydroid . Found in pools, quiet streams, and spring ponds, usually on the underside of leaves of aquatic vegetation, especially lily pads.

Radiates

.Are radially (or biradially) symmetrical, a form of symmetry in which body parts are arranged concentrically around an oral-aboral axis. .Both Cnodaria and Ctenophora are DIPLOBLASTIC because the epidermis and gastrodermis develop from the two embryonic germ layers (ectoderm and endoderm) .Have a tissue level of organization

Hydrotheca

a cup like piece of perisarc that protects hydranths in thecate hydroids

Obelia (phylum Cnidaria)

A colonial hydroid found in marine waters and attached to seaweeds, rocks, shells, and other objects

Gonionemus (Phylum Cnidaria)

A hydromedusa= Hydrozoan medusa Medusa fairly large and suitable for continued study of the hydroid life cycle Found in shallow protected coastal and bay areas along both coasts of U.S.

Hydranth

Nutritive polyps

Exumbrella

The convex outer (aboral) surface

Gonopore

Opening of the reproductive systems of an organism to the outside.

Subumbrella

The concave (oral) surface of gonionemus

Eumetazoans

True multicellular animals (Cnidaria and Ctenophora)

Medusa buds

one of the buds of a hydroid destined to develop into a gonophore or medusa.

Class Hydrozoa

1. Hydra 2. Obelia 3. Gonionemus All have cnidocytes, stinging cells

Two important metazoan features shared by all radiates are:

1. Two embryonic primary GERM layers (ectoderm and endoderm) that are homologous to those of more complex metazoa and 2. Internal space afor digestion, the gastrovascular cavity, which lies along the polar axis and opens to the outside by a mouth.

Dimorphism

The presence in a species of more than one morphological kink of individual--is common in Cnidarians but absent in ctenophores

Gonangium

a reproductive polyp of a colonial hydroid, giving rise asexually to medusa buds. Origin of gonangium.

Physalia (Phylum Cnidaria)

A hydrozoan

Polymorphism

a discontinuous genetic variation resulting in the occurrence of several different forms or types of individuals among the members of a single species. A discontinuous genetic variation divides the individuals of a population into two or more sharply distinct forms.

Nematocyst

a stinging cell that is used to inject a toxin into prey

Basal disc

base of a hydra, adheres to substrate or sometimes surface of water

Coenosarc

cellular body wall surrounding gastrovascular cavity

Hypostome

elevated mound of tissue that expands or contracts to regulate size of mouth opening

Cnidocyte

nematocyst-containing stinging cell on a cnidarian's tentacle

Gonotheca

parts of the obelia hydrpoid colony

Perisarc

sheath covering the stalk and branches of a hydroid