Fig. 1. Micrographs of cnidocytes isolated from the tentacles of Physalia physalis. (A) A low power micrograph showing the absence of other cell types. (B) A combined Normarski/fluorescence micrograph showing representatives of the two size classes of cnidocytes present in these preparations. Blue fluorescence of DAPI marks the nucleus of the cells. (C,D) Higher power Normarski/fluorescence micrographs of a single large (C) and small (D) cnidocyte. The DAPI-stained nucleus is very evident at the base of the cyst in each cell. The cnidocil at the apical end of each cell is marked with an arrow. Note the cytoplasmic projections at the base of the cells. Scale bars: 200 µm (A), 50 µm (B), 20 µm (C,D).