Jellyfish Life Cycle Diagram – Aurelia Scyphistoma Labeled

All 14 stages and parts on the diagram

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The cycle 8

Scyphistoma (polyp) The small polyp stage, fixed to a hard surface. It feeds, and it can bud off more polyps.
Planula A tiny larva that swims by its cilia. It settles on a hard surface and becomes a polyp.
Strobila The polyp divided into a stack of discs. Each disc breaks away as an ephyra.
Ephyra A tiny young jellyfish with eight lobes. It swims off and grows into a medusa.
Adult medusa The grown jellyfish, the stage that makes eggs or sperm. Each one is either male or female.
Egg A single cell made by a female medusa. Once fertilized it develops into a planula.
Sperm Tiny swimming cells released by a male medusa. They reach the eggs of a female through the water.
Young medusa The ephyra after its notches have filled in. It keeps growing into an adult medusa.

The polyp stages, enlarged 6

Tentacles A ring of long tentacles around the mouth. They point upward and outward.
Mouth The opening at the top of the polyp. It sits on a short raised cone, inside the ring of tentacles.
Stalk The narrow lower end of the polyp. It holds the polyp to the surface.
Bud A new polyp growing from the first one. Budding makes more polyps without eggs or sperm.
Discs The saucer-shaped pieces a strobila is divided into. The top ones break away first.
Lobes of the ephyra The eight arms of an ephyra. Each is split at its tip, with a sense organ in the notch.

How this list was compiled: Every name was checked on 2026-10-03 in at least two sources, for facts only and with nothing copied. R. W. Hegner, College Zoology (1912, public domain), a scyphozoan jellyfish, Aurelia, https://archive.org/details/collegezoology00hegn. T. J. Parker and W. A. Haswell, A Text-book of Zoology, volume 1 (1910, public domain), Aurelia aurita: development and life-history, https://archive.org/details/textbookofzoolog00park. Wikipedia: Jellyfish (life cycle), Scyphozoa, Strobilation and Aurelia aurita, https://en.wikipedia.org/wiki/Jellyfish. Animal Diversity Web, University of Michigan Museum of Zoology, Aurelia aurita, https://animaldiversity.org/accounts/Aurelia_aurita/. A. G. Mayer, Medusae of the World, volume 3, the Scyphomedusae (1910, public domain), https://archive.org/details/medusaeofworld03mayo. Unofficial study material, not affiliated with any textbook, course or exam; check your own course material. Licence: own work

The drawing: Drawn for this site on 2026-10-03 from plain geometry; nothing traced. Licence: own work

How it works

Here is the Aurelia scyphistoma labeled in its place in the life cycle of the moon jelly. The first view shows the cycle as a ring, from planula to medusa. The second enlarges the scyphistoma and the strobila.

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The cycle

Read the ring clockwise from the adult medusa. Medusae make eggs and sperm. A fertilized egg becomes a planula, which settles and grows into a scyphistoma, a small polyp. The polyp turns into a strobila, a stack of discs. Each disc swims off as an ephyra and grows into a medusa.

The polyp stages

The second view shows the scyphistoma with its tentacles, mouth, stalk and a bud, then the discs of a strobila and the eight lobes of an ephyra. Press Quiz me to find each stage.

Scyphistoma and strobila are the same polyp at two times: before and after it divides into discs.

Questions and answers

What is a scyphistoma?

The polyp stage of a jellyfish such as Aurelia. A planula larva settles on a hard surface and grows into this small polyp, with a stalk, a mouth and a ring of tentacles. Older books also call it a scyphula or hydra-tuba.

What is the difference between a scyphistoma and a strobila?

They are the same polyp at two times. A scyphistoma feeds and buds. When it divides across into a stack of discs it is called a strobila, and the discs break away as ephyrae.

What are the stages of the Aurelia life cycle?

Egg and sperm from adult medusae, a swimming planula larva, the scyphistoma or polyp, the strobila, the ephyra and the young medusa, which grows into an adult.

What is an ephyra?

A tiny young jellyfish set free from a strobila. Its disc is drawn out into eight lobes with deep notches between them. As it grows the notches fill in and it becomes a round medusa.

What is strobilation?

The way a jellyfish polyp divides across its body into a stack of discs, each of which becomes an ephyra. One polyp can set free a number of young jellyfish this way.