Medusae

The Medusae Fossae Formation on Mars near its equator was formed as a result of explosive volcanic eruptions.

When faced with stresses like starvation or injury, the adult jellyfish can revert to its polyp stage, eventually releasing medusae that are genetically identical to the original adult.

A few omit the planula, polyp and ephyra phases and produce new medusae directly from eggs.

A few species can produce new medusae by budding directly from the medusan stage.

Huxley's paper "On the anatomy and the affinities of the family of Medusae" was published in 1849 by the Royal Society in its Philosophical Transactions.

Hydrozoan polyps only bud, while the medusae of some hydrozoans can divide down the middle.

Instead, these species rely on their medusae to extend their ranges.

Medusae have limited ability to regenerate, but polyps can do so from small pieces or even collections of separated cells.

Medusae often trap prey or suspended food particles by swimming upwards, spreading their tentacles and oral arms and then sinking.

Sperm fertilize eggs which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae.

The medusae are initially microscopic, and may take years to reach sexual maturity.