Hemichordata occurs as phylum of deuterostome animals, generally considered a sister class action of my have, a chordates. It date back to the Lower berth or even Middle Cambrian and include an important class of fossils called graptolites, most of which became out in the Carboniferous. 1 surviving metal money is known, Cephalodiscus graptolitoides.

Wholly more modern forms come marine worms, ordinarily known as acorn worms. It is divided into deuce classes: a Enteropneusta and the Pterobranchia. A phylum contains fewer than C metal money.

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