ACORN WORMS (HEMICHORDATA)
The acorn worms are a small group of exclusively marine worm-like animals. Turk, in Spalding, A. (Ed.) 1997, has reviewed the status of this group in Cornish waters. The phylum Hemichordata comprises three classes of which only the Enteropneusta or acorn worms are considered below. Howson (in Howson & Picton, 1997) lists nine species in British waters, three of which are recorded from the coasts of Cornwall and the Isles of Scilly. Knight-Jones and Ryland (1990) provide keys and descriptions of all the presently known British species.