Cnidaria Lab


























































































































































































Whole Mount-




























Live Specimens


Branching Anemone:






















Banded Tube-Dwelling Anemone:







Giant Anemone:


Stony Corals:

Ivory Bush Corals:






























Gorgonian Corals:

Slimy Sea Plumes:





















Colorful Sea Rod:












Freshwater Hydra:

-No Magnification:



















Hydroid Skeleton:

















Different hydroid:

Phylum Ctenopora:

-Not cnidarians.










Preserved Jelly:










Polyp: The sedentary form of a cnidarian. A tube like structure with a mouth on top and feeding tentacles surrounding said mouth.

Medusae: The free-floating (pelagic) form of a cnidarian, who has a medusae phase, that floats in the water column to feed and reproduce. The reproductive phase of cnidarians who have a medusae phase, include sea jellies.

Mouth: An opening through which food is directed to the gastrovascular cavity.

Tentacle: The noodle like structure that can have many functions including feeding and locomotion.

Gastrovascular Cavity: The organ that facilitates digestive and circulatory functions. The cavity that digests food and moves nutrients across the body, also removes waste.

Cnidocyte: A cell whose function is to produce Cnidae and eject them when stimulated. Also called a nematocyst.

Cnidae: A sharp, pin-like structure that is ejected from a cnidocyte to stick into the target and release a toxin. The cnidae caused death or immobilization to prey and pain to predators (or larger organisms that come into contact).

Operculum: A cover to the nematocyst that acts like a hinge.

Cnidocil: A hairlike structure on a nematocyst that, when stimulated, releases the cnidae.

Manubrium: The structure hanging from the bell of the medusae that holds the mouth at its tip.

Radial Canal: A canal that sits at the center of the bell in the medusae structure which connects the mouth and gastrovascular cavity to the ring canals which facilitates exchange of material.

Bell: The outer layer of the medusae which gives it the “bell” shape.

Oral Arms: Tentacles located around the mouth which bring food items into the mouth.

Gastric Pouch: A section of the gastrovascular cavity in larger jellies (scyphozoans) that contains a gastric filament. Scyphozoans typically have four gastric pouches that make up the gastrovascular cavity.

Gonad: A structure that produces sex cells located in the gastroderm.

Gastric Filament: A tentacle projection from a gastric pouch which releases digestive enzymes.

Zooanthellae: Dinoflagellates that live inside some cnidarians, corals, which photosynthesize. They have an endosymbiotic relationship with cnidarians.

Planula Larvae: a free swimming form of a cnidarian. This forms the fertilized egg of a medusae in scyphozoans or the polyp of anthozoans.

Scyphistoma: The stage of a scyphozoan when it forms a polyp which reproduces asexually to produce medusae.

Strobila: The pre-medusae structures of the scyphozoan polyp which appear as striations on the polyp.

Strobilization: The process of producing strobila which are then released to become medusae.

Ephyra: The free-swimming larva of a scyphozoan which grows into a medusae once it matures.

Hydromedusae: The medusae form of a hydrozoa.

Velum: Tissue around the bell which acts as a muscle for locomotion.

Stolon: A branch-like projection of a hydrozoan which gives rise to another hydrozoa via budding.

Hydranth: A feeding zooid of a hydroid colony.

Perisarc: The outer layer of a hydroid colony. Usually made of chitin.

Hydratheca: a cup shaped projection of the perisarc that protects tentacles that retract into it.

Thecate: a type of coral or hydrozoan that has theca, a cup structure that holds a coral polyp or projecting feature of a hydrozoan.

Athecate: A type of coral or hydrozoan without theca.

Zooids: An individual, usually of a colony, which was produced by budding from another individual in said colony. Hydrozoans.

Gastrozooid: A zooid which contains features and structures used for digestion.

Gonozooid: A zooid which holds and controls the reproductive features of the hydrozoan colony.

Dactylozooid: A zooid that has tentacle like features used for prey capture and defense that contains nematocysts.

Siphonoglyph: a groove containing cilia that are connected to the mouth which act to bring water flow to the mouth.

Pharynx: A tube, in anthozoans, that connects the mouth to the coelenteron (gastrovascular cavity).

Mesenteries: Sheet-like extensions of the body wall into the gastrovascular cavity which act to increase the surface area of the GV cavity.