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Phylum Hemichordata Glandiceps hacksi, (Enteropneusta) from Tomiyama et. al., 1970

The hemichordates include the class Enteropneusta (acorn worms) and the class Pterobranchia . There are about 80 living species of Enteropneusta , which are marine and mostly intertidal organisms that live buried in fine sediments or under rocks. Their size ranges from a few centimeters to about 2 meters in length, and a few species live in the deep sea. Most Enteropneustes are direct deposit feeders (they ingest sediment and digest the organic matter). Some are also suspension feeders (removing organic particles from the water column). The Pterobranchs are all small, mostly colonial organisms, each zooid typically less than 1.2 cm in length, and colonies rarely exceeding 10 cm. They are ciliary mucus suspension feeders (a mucus net is formed among their extended tentacles, and as organic particles are trapped in the mucus the entire mass is slowly swept by cilia into the mouth).

Rhabdopleura sp. (Pterobranchia) from BIODIDAC, Univ. of Ottowa

References: Barnes, 1980. Barnes, Calow, and Olive, 1993 BIODIDAC, Univ. of Ottowa Meglitsch & Schram, 1991 Brusca & Brusca, 1990.

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