DMH said:And? I doubt any party is going to encounter larval echinoderms and thus I only mentioned the adult form.
Still applies. Symmetry in animals is based on their original condition, not what develops later in life. Echinoderm larvae are bilaterally symmetrical, so the adult form is accounted bilaterally symmetrical. As a matter of fact, you take a good long look at the echidnoderms you'll find that they exhibit all the hallmarks of bilateral symmetry even as adults.
Out of the 36 phyla of inverts, 18 are not worms- sponges, arthropods, molluscs, comb jellies, echinoderms, cnidarians (jellyfish and coral), rotifers and the very cool kinorhynchs* among them.
Now that I got wrong.
Where did you come up with crustacean? That isn't even a phylum.
A catch-all term for a number of phyla with a hard exoskeleton. In vertebrates you have thecodonts (reptiles) and condylarths (mammals). In the case of the crustaceans, they all look pretty much alike to the casual observer, so they got called "crustaceans". Only later with close study did the differences in basic body plan become apparent.
All adult echnioderms have radial symmetry.
See above. Besides which, what matters is not the adult shape; which isn't really radial to begin with.
*These guys would make great monsters- armored, aquatic ambush predators that are very tough to damage because of their armor. And the loricferians look like pineapples with all kinds of spikes on its head. The glomerus from the plane of Mineral (from a Dragon issue) reminds me of them.
So somebody from the Plane of Mineral took home a pet kinorhynch for their aquarium and it got loose.



