Definition

Noun: 1. The flat, ciliated, free-swimming larval stage of hydrozoan coelenterates: A planula is a tiny, multicellular organism that represents an early phase in the life cycle of certain aquatic animals, such as jellyfish and corals. It is characterized by its flattened, oval shape, its covering of hair-like structures called cilia used for movement, and its ability to swim freely in water before settling and developing into its next form.

Usage Examples

• Noun:
  • After fertilization, the egg develops into a planula.
  • The planula uses its cilia to swim until it finds a suitable surface to attach to.
  • Biologists study the planula stage to understand the early development of cnidarians.

Advanced Usage

• "Planula larva": This is a more specific term, explicitly identifying the planula as a larval form. It is often used in technical biological contexts.
  • The coral releases its planula larva into the water column during a synchronized spawning event.

Variants and Related Words

• Planulae (n): The plural form of planula.
  • The water was teeming with countless planulae after the coral spawn.

Synonyms

• Larva: A more general term for the immature, free-living form of an animal that undergoes metamorphosis.
• Hydrozoan larva: A specific term indicating the larval stage of animals belonging to the class Hydrozoa.

Noun

1. the flat ciliated free-swimming larva of hydrozoan coelenterates