Introduction

The lophophorates are a group of three phyla, sometimes given taxonomic status collectively as the Lophophorata or Tentaculata, and having in common the presence of a special kind of feeding organ, made up of a ring of ciliated tentacles surrounding the mouth, termed a lophophore. They are not particularly familiar to the layman, and rarely receive attention in introductory zoology courses, but are nevertheless of considerable importance in interpreting the pattern of the animal kingdom, so are justifiably given a chapter to themselves in this book.

The most important of the three phyla nowadays is the moss animals (bryozoans or ectoprocts), individually tiny but with the zooids assembled as often substantial colonies, diverse in form but commonly sheet-like or erect and branching. The bryozoans (reviewed by Ryland 1970; Woollacott & Zimmer 1977) are actually amongst the larger phyla in terms of species number. They are very frequently met with in the lower littoral zone, where they may dominate the filter-feeding community, and they may also be washed up as dried remains on the strandline; most people will therefore have met specimens of these creatures, though they may have misinterpreted them as plant remains. A second group is the lamp shells or brachiopods, reviewed by Rudwick (1970). They resemble molluscan bivalves but have two dissimilar calcareous shell valves that are dorsal and ventral (rather than identical valves that are bilateral), and within which a spiral array of tentacles may be visible. The brachiopods are not abundant now, but have been dominant in previous eras and their fossilised remains are invaluable to geologists for dating purposes.