Hemichordates are a phylum of marine invertebrate animals. They are the sister group of echinoderms and most have a soft, often worm-shaped, body. They first appear in the fossil record in the Cambrian period over 510 million years ago.
Hemichordates are a phylum of marine invertebrate animals. They are the sister group of echinoderms and most have a soft, often worm-shaped, body. They first appear in the fossil record in the Cambrian period over 510 million years ago.