Now we know that they were primitive hemichordates -- perhaps the most ... digging into the sea floor may simply have been a safer option. Certainly, modern-day acorn worms have adopted this ...

Some 500 million years ago, miniscule sea worms built and lived in ventilated tubes that stuck up from the ocean floor like tiny ... They put it with hemichordates, a group of marine invertebrates ...

Hemichordates occur from intertidal to abyssal ... of acorn worms were observed forming meandering tracts on the ocean floor, and range in size up to 60 cm in length and 12 cm in width.

Many members of both groups live on the ocean floor and feed on organic particles in the sediment ... sea cucumbers) and the Hemichordates (e.g. acorn worm). “Our research shows that Xenoturbellida ...

On this basis, they tentatively designated these deep-sea worms as a new group of hemichordates that they ... emptied its gut and floated off the sea floor. Why don't these abyssal enteropneusts ...