- any tunicate, especially a sessile ascidian, so called from its habit of contracting its body and ejecting streams of water when disturbed.
Origin of sea squirt
First recorded in 1840–50
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for sea squirt
This gap was filled some years ago by the discovery of the lancelet—Amphioxus—and the young of the sea-squirt—Ascidia.
- any minute primitive marine animal of the class Ascidiacea, most of which are sedentary, having a saclike body with openings through which water enters and leavesSee also ascidian
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- Any of various tunicates of the class Ascidiacea, having a transparent sac-shaped body with two siphons. One of the siphons is used to draw water (carrying oxygen and food particles) into the body, while the other expels it. Sea squirts are free-swimming as larvae but sessile as adults. Like other tunicates, sea squirts are chordates, but they have a notochord only in the larval stage.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.