BellThe body of the jellyfish, shaped like an umbrella. It tightens and relaxes to push the animal through the water.
TentaclesA fringe of short fine threads all round the rim. They carry stinging cells and catch small animals that drift into them.
Oral armsFour long frilled arms that hang from the corners of the mouth. They carry stinging cells and move food up to the mouth.
StomachA hollow in the middle of the bell where food is digested. Its only way in or out is the mouth.
MesogleaThe thick, clear jelly between the outer skin and the inner lining. It makes up most of the bell and gives it its shape.
ManubriumA short stalk that hangs from the middle of the underside. The mouth is at its tip. In a moon jelly it is very short.
From below 7
MouthThe one opening of the body, four-sided in a moon jelly. Food goes in through it, and waste comes out the same way.
GonadsFour horseshoe-shaped organs that make eggs or sperm. They show through the top of the bell and are how a moon jelly is known.
Gastric pouchesFour pockets that open off the stomach. One gonad lies in the floor of each.
Radial canalsThin tubes that run from the stomach out to the rim. They are set like the spokes of a wheel, and some of them branch.
Ring canalA narrow tube that runs all the way round the rim. Every radial canal opens into it.
Rhopalia (sense organs)Eight small sense organs, one in each notch of the rim. They help the jellyfish keep its balance and tell light from dark.
Marginal lappetsSmall flaps on the rim, one on each side of every notch. A sense organ sits between each pair.
How this list was compiled: Every name checked on 2026-10-01 in two sources. Wikipedia, Jellyfish (Anatomy), Aurelia aurita and Rhopalium, https://en.wikipedia.org/wiki/Jellyfish. NOAA National Ocean Service, What are jellyfish made of?, https://oceanservice.noaa.gov/facts/jellyfish.html. Animal Diversity Web, University of Michigan Museum of Zoology, Aurelia aurita, https://animaldiversity.org/accounts/Aurelia_aurita/. T. J. Parker and W. A. Haswell, A Text-book of Zoology, volume 1 (1910, public domain), the common jelly-fish, https://archive.org/details/textbookofzoolog00park. R. W. Hegner, College Zoology (1912, public domain), Aurelia, https://archive.org/details/collegezoology00hegn. Licence: own work
The drawing: Drawn for this site on 2026-10-01 from plain geometry; nothing traced. Licence: own work
How it works
This jellyfish anatomy diagram is unlabeled: a moon jellyfish seen from the side, with the bell drawn see-through, and again from below. Thirteen lines end in empty space, and the print adds a Name and Date row: a jellyfish diagram worksheet with a key.
Read the full guide
The word bank
The paper carries the lines and no names, so the names can go on the board. Side view, six: bell, tentacles, oral arms, stomach, mesoglea, manubrium. View from below, seven: mouth, gonads, gastric pouches, radial canals, ring canal, rhopalia, marginal lappets.
Follow each line to its end
A line names the part where it stops, not the parts it crosses. On the side view the line from the upper left crosses the bell and stops on the stomach, and the line from the lower right crosses the fringe and stops on the manubrium. From below, the longest line stops at the mouth in the middle.
The line that stops on a horseshoe is for the gonads. The line into the round pocket beside a horseshoe is for the gastric pouches.
Three lines stop at the rim: on a dot in a notch (rhopalia), on a flap (marginal lappets) and on the heavy circle (ring canal).
Questions and answers
What kind of jellyfish is on the diagram?
A moon jellyfish, Aurelia aurita, also called the common jellyfish or saucer jelly. Both zoology textbooks named in the sources take its genus, Aurelia, as their example.
Do all jellyfish have the same parts?
The plan is shared and the details differ. A box jellyfish has a squarish bell with a shelf, the velarium, folded in at its rim, and its tentacles hang from a stalk at each of four corners. This sheet's names fit a moon jellyfish.
What is left off the unlabeled jellyfish diagram?
The two thin cell layers, epidermis outside and gastrodermis inside, and the stinging cells on the tentacles and oral arms. Each is too thin or too small to draw at this size. The stages of the life cycle have a diagram of their own.
Is there an answer key for the jellyfish worksheet?
Yes. The key is the same sheet with every name on its line. Three are shortened to fit: Pouches for gastric pouches, Rhopalia for rhopalia (sense organs) and Lappets for marginal lappets.