medusan
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Definition
Noun: 1. A free-swimming, gelatinous, umbrella-shaped stage in the life cycle of certain coelenterates (cnidarians): A "medusan" is one of the two principal body forms of animals like jellyfish, sea anemones, and corals. It is the mobile, often sexually reproductive phase, characterized by a bell-shaped body and trailing tentacles.
Examples of Usage
- The life cycle of many jellyfish alternates between a stationary polyp and a free-swimming medusan.
- The medusan form is responsible for the dispersal of the species across the ocean.
- Under the microscope, the delicate structure of the medusan was clearly visible.
Advanced Usage
- "Medusan stage": This phrase explicitly refers to this specific phase in an organism's development.
- The planula larva eventually develops into the medusan stage.
- The term is often used in contrast to the "polyp" form, which is the sessile, asexual stage in the same life cycle.
Variants and Related Words
- Medusa (n.): This is the more common and general term for the same life stage. "Medusan" is the adjectival form used as a noun.
- Medusoid (adj./n.): Having the form or characteristics of a medusa; can also be used as a noun synonym for medusan.
- Jellyfish (n.): A common name for many animals that exist primarily or exclusively in the medusan form.
Synonyms
- Medusa
- Medusoid (when used as a noun)
- Jellyfish (in common, but not strictly scientific, usage for the adult form)
Notes on Meaning
The word "medusan" is primarily a scientific term used in marine biology and zoology. Its meaning is very specific to the field of coelenterate (cnidarian) life cycles and is not used in everyday conversation. It refers exclusively to a biological form, not to the mythical creature Medusa.
Noun
- one of two forms that coelenterates take: it is the free-swimming sexual phase in the life cycle of a coelenterate; in this phase it has a gelatinous umbrella-shaped body and tentacles