This identification guide is the result of intensive sampling of shallow-water habitats in Bocas del Toro during 2003 and 2004. The guide is designed to aid in identification of a selection of common macroscopic marine invertebrates in the field and includes 95 species of sponges, 43 corals, 35 gorgonians, 16 nemerteans, 12 sipunculeans, 19 opisthobranchs, 23 echinoderms, and 32 tunicates. Species are included here on the basis on local abundance and the availability of adequate photographs. Taxonomic coverage of some groups such as