1. A marine animal of the class Ascidiacea, typically a small, barrel-shaped or sac-like creature that filters food from seawater; also called a sea squirt.
Usage: biology; plural: ascidiae or ascidias

Examples

• The ascidia attaches itself to rocks and coral on the ocean floor.
• Ascidiae are filter feeders that draw water through their bodies to extract plankton.
• Marine biologists study ascidiae to understand the evolution of vertebrates.
• The ascidia's simple body plan makes it an important model organism in developmental biology.
• Divers often observe colorful ascidiae clustered together on underwater surfaces.