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
A part of a moon jellyfish is named and you tap it on the drawing. In this jellyfish anatomy quiz the bell is drawn see-through, so the stomach and the mesoglea inside it can be tapped too.
Read the full guide
From the side: what gets mixed up
The tentacles are the short threads round the rim; the oral arms are the four long frilled ribbons under the middle. The mesoglea is the dotted layer in the top of the bell, the stomach is the flat oval beneath it, and the manubrium is the short tube below that.
From below: three pairs
A gastric pouch is the round pocket, and the gonad is the horseshoe inside it. The radial canals are the spokes, and the ring canal is the heavy circle they reach. A rhopalium is the dot in a notch of the rim; the lappets are the flaps on either side of it.
An older textbook may print umbrella for the bell, circular canal for the ring canal and tentaculocysts for the rhopalia.
Questions and answers
What parts are on the jellyfish anatomy quiz?
Thirteen: bell, tentacles, oral arms, stomach, mesoglea and manubrium from the side, then mouth, gonads, gastric pouches, radial canals, ring canal, rhopalia and marginal lappets from below. The stinging cells are too small to draw and are not asked.
What type of symmetry does a jellyfish have?
Radial symmetry: its parts are set round a central axis. From below, a moon jellyfish shows them in fours and eights, with four oral arms, four gastric pouches, four gonads and eight notches in the rim.
Where is the mouth of a jellyfish?
Under the bell, in the middle, at the tip of the manubrium. That is why the quiz asks for it in the view from below: it is the four-cornered opening where the four oral arms meet.