Light microscopy of wet mounts of discharged nematocysts of <i>Heteroxenia fuscescens</i> stained by cresyl violet.

<p><b>a</b>. Atrichous isorhiza nematocysts isolated from polyp cavity, zooxanthellae indicated by arrow. <b>b</b>. Novel type of nematocysts adjacent to surface of tentacular pinnules, zooxanthellae indicated by arrow. <b>c</b>. Enlarged view of a discharged atrichous isorhiza nematocyst-type from the gastrovascolar cavity. <b>d</b>. Novel macrobasic-mastigophore nematocyst-type from pinnules.