from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. cnidarian
from the GNU version of the Collaborative International Dictionary of English
- n.pl. A comprehensive group equivalent to the true Cœlenterata, i. e., exclusive of the sponges. They are so named from presence of stinging cells (cnidae) in the tissues. See coelenterata.
from The Century Dictionary and Cyclopedia
- Those Cœlentera which have thread-cells or cnidœ; the Cœlenterata, with the exception of the sponges. See Cœlentera.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. hydras; polyps; jellyfishes; sea anemones; corals
Sorry, no etymologies found.
A short survey to a depth of 20 m revealed 168 species of finfish, 60 species of cnidaria, including corals, 8 molluscs, 14 sponges, 11 echinoderms, 15 arthropods and 8 annelid worms.
Did the cnidaria have Hox clusters, suggesting that the clustered Hox genes were a very early event in evolution, or do they lack them and therefore evolved an independent set of mechanisms for specifying positional information along the body axis?
Without going into the difficult question of the origin of this stem, we must emphasise the fact that the vertebrate stem has no direct affinity whatever to five of the other ten stems; these five isolated phyla are the sponges, cnidaria, molluscs, articulates, and echinoderms.
There are four stems belonging to the coelenteria: the gastraeads ( "primitive-gut animals"), sponges, cnidaria, and platodes.
It is certainly a fact of the greatest interest and instructiveness that animals of the most different stems -- vertebrates and tunicates, molluscs and articulates, echinoderms and annelids, cnidaria and sponges -- proceed from one and the same embryonic form.
In most of the cnidaria and many of the annelids (worm-like animals) they remain unchanged throughout life.
(Sagitta), and many of the echinoderms and cnidaria, such as the common star-fish and sea-urchin, many of the medusae and corals, and the simpler sponges (Olynthus).
This simplest of all the cnidaria has, it is true, a crown of tentacles round its mouth.
This we find in the lower cnidaria and worms, as well as in the more highly-developed molluscs, echinoderms, articulates, and vertebrates.
Among others are echinoderms, including starfish, sand dollars and sea cucumbers; porifera, which includes sponges; and cnidaria, including sea anemones, corals and jellyfish.