Figure 3. Gonionemus sp. Micromorphology of tentacles and nematocysts.

(A–C) Tentacle parts with nematocyst batteries and adhesive pads. Note dark pigmented mid-line in tentacles, yellow-reddish pigments in batteries and around adhesive pad. (Inset B) LM. Euryteles, note shaft and tubule. (D–K) LMs. Tentacle nematocysts. Undischarged and discharged microbasic euryteles and small microbasic b-mastigophores. Note shaft, tubule, lid and apical capsule opening (*). (E) Microbasic eurytele with broad, rod-shaped shaft, pointed apically and microbasic b-mastigophore with slightly bent, narrow shaft, following the convex capsule side. (F and G) Microbasic b-mastigophores. Note shaft and tubule pattern. (H–J, inset) Discharged microbasic euryteles. Note broad shaft with spined distal swelling, rounded lid, difference in diameter of shaft and distal tubule. (J) Note spine pattern on distal tubule. (I and K) Microbasic b-mastigophores. Narrow shaft with unclear spine-pattern. Abbreviations: *marks apical capsule opening; ap, adhesive pad; b, b-mast, microbasic b-mastigophore; dt, distal tubule; eu, eurytele; l, lid; nb, nematocyst battery; sh, shaft; sp, spines; tu, tubule. Photo credits: Carina Östman.