Fig. 1

Type and distribution of cnidocytes in N. vectensis. a Microbasic p-mastigophores have a thick shaft which ends in a distinctive v-shaped notch (arrow). b Basitrichous isorhizas are variable in size (compare left and right DIC images) and have a thin shaft lacking a v-shaped notch and a tubule which is visible through the capsule (arrows). c Spirocytes can be identified by the regularly spaced coiled tubule and the lack of a visible capsule (arrow); a basitrichous isorhiza is shown for comparison (arrowhead). d, e The mesenterial filaments and pharynx are populated largely by microbasic p-mastigophores and large basitrichous isorhizas. f The body wall is populated by small basitrichs, and g the tentacle tips are populated by large basitrichous isorhizas (arrowheads in c, g) and spirocytes (arrows in c, g). Only nematocytes (basitrichous isorhizas and microbasic p-mastigophores) can be labeled using DAPI, indicated by yellow color in the cartoons (a, b). Scale bars in a–c represent 5 μm. All images are DIC micrographs