Cnidaria Lab


Aurelia strobila: 100x



Aurelia planulae: 400x



Aurelia scyphistoma: 400x and 100x


Aurelia ephyra: 400x and 100x

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Hydra Budding: 100x and 40x

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Hydra nematocysts: 400x and 100x

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Hydra w.m: 100x


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Obelia w.m: 100x


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Obelia medusae: 100x


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Phylum Ctentophora

Comb Jelly


Live Specimens

Anemone and Cup Corals: 8x

Stony Coral: 10x


Freshwater Hydra: 40x and 100x

Hydroids (colonial): 8x


Ivory Bush Coral: 8x


Zoanthid: 8x


  • polyp: Colonies of coral polyps are what form the actual coral.
  • medusae: A free-swimming  form of a coelenterate such as a jellyfish. They typically having an umbrella-shaped body with stinging tentacles around the edge. In some species, medusae are a phase in the life cycle that alternates with a polypoid phase.
  • mouth: It is typically surrounded by a crown of tentacles.
  • tentacle:A  flexible limb or appendage in an animal such as jellyfish, especially around the mouth of an invertebrate. They are used for grasping, moving about, or bearing sense organs.
  • gastrovascular cavity: The primary organ of digestion and circulation in two major Cnidarians and Platyhelminthes. The cavity can be extensively branched into a system of canals.
  • cnidocyte: An explosive cell containing one giant secretory organelle that defines the phylum Cnidaria.
  • cnidae: This is what makes touching a tentacle on a jellyfish sting.
  • nematocyst: Specialized cnidae that are characteristic of scyphozoan and other types of cnidarians.
  • operculum: The cover that rapidly opens a cnida on a cnidarian.
  • cnidocil: A hairlike sensory process projecting from the surface of a cnidoblast. It is believed to trigger the discharge of the nematocyst.
  • discharged: Many cnidarians discharge nematocysts.
  • undischarged: An undischarged nematocyst is housed within a cell known as a nematocyte.
  • manubrium: The tube that connects the stomach on one end to the the four-parted mouth on the other.
  • radial canals: In the medusae of Cnidaria, it is an arrangement of the gut cavity where the mouth leads to the stomach, hanging from the centre of the umbrella, from where canals extend to the outer rim of the umbrella where they are linked by a ring canal around the periphery. There are typically four canals.
  • bell: The umbrella shaped body of many Cnidarians like jellyfish.
  • oral arms: There are usually four which are located around the mouth and hold the stinging cells that are used to inject potential prey or predators with venom.
  • gastric pouch: The scyphozoan gastric cavity is divided into 4 gastric pouches that contain a tentacle-like projection of gastrodermis called a gastric filament which contain numerous gland cells that secrete digestive enzymes.
  • gonad:these release ova and sperm into the water in the breeding season.
  • gastric filament: A filament lined with nematocysts that kill living prey entering the stomach of a jellyfish.
  • zooanthellae: Single-celled dinoflagellates that are able to live in symbiosis with a variety of different cnidarians.
  • planula larvae: A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species.
  • scyphistoma:  When the planula larva attaches itself to a hard surface and transforms into a polyp which is also known as a scyphistoma.
  • strobila: The polyps are stacked like plates and the structure is called a strobila.
  • strobilization: The process where the polyp forms ephyrae breaks off and develop into adult jellyfish.
  • ephyra: Jellyfish larvae in the medusa form
  • hydromedusae structure:  This structure possess long hollow tentacles for capturing prey. These tentacles have many stinging nematocysts for immobilizing the prey.
  • velum:  It is a rim of tissue around the margin of the bell of certain cnidarians.
  • stolon: The polyps are connected by tubes called stolons and the whole is enclosed in a common skeleton.
  • hydranth: A feeding polyp that resembles a Hydra.
  • perisarc: A sheet of chitin and proteins that surrounds the hydrocaulus.
  • hydratheca: Exoskeletal cups that protect the feeding polyps.
  • thecate: Leptomedusae or Leptomedusa, commonly called thecate hydroids, are a cnidarian order in the subclass Leptolinae.
  • athecate: The polyps of athecate hydroids are not protected by a holster.
  • zooids: Have many different purposes such as defense, reproduction and catching prey. They are the individuals that make up a colony that are all joined in some way.
  • gastrozooid:  They feed, dactylozoids capture prey, and gonozooids give rise to medusoids with gametes.
  • gonozooid: The few female zooids enlarge to form spacious brood chambers.
  • dactylozooid: They look like tentacles but are actually defensive polyps.
  • siphonoglyph: A ciliated groove at one or both ends of the mouth of sea anemones and some corals that is important for respiration and the maintenance of internal pressure.
  • pharynx: A stout tube hanging down from the mouth into the coelenteron. In some anthozoans septa attach the pharynx to the body wall.
  • mesenteries: A membrane inside the body cavity of an animal.