Nematocyst: Intracellular stinging capsule, which possesses a thick double wall that encloses a tubule of varying construction and armature. Nematocysts are basophilic, which means they are stained readily with basic dyes. There are at least 25 types of nematocysts within Phylum Cnidaria, grouped into three or four functional groups (Kass-Simon and Scappaticci, 2002). Six types are found in Anthozoa, two of which are exclusive to the class. Nematocysts are a type of cnida; the defining feature of the Phylum Cnidaria.

See Also: Atrich, Basitrich, Cnidae, Holotrich, Hoplotelic, Macrobasic amastigophore, Microbasic amastigophore, Microbasic b-mastigophore,

Microbasic p-mastigophore, Nematoblasts, Nematosomes, Nematospheres, and Spirocyst


Click here to see a Nematocyst Identification Database

Click here to see a table clarifying Nematocyst Nomenclature


Images of Various Nematocysts: (species names are linked to the Hexacorallian database)

Species: Anthopleura mariscali

Fig. 3. Representative cnidae from *Anthopleura mariscali*, new species. Scale bar = 20 µm; refer to Table 1 for size and distribution. A. spirocyst. B. Basitrich. C. S-shaped basitrich. D. Small basitrich. E. Microbasic *b*-mastigophore I. F. Microbasic **-mastigophore II. G. Microbasic *p*-mastigophore. H. holotrich I. I. holotrich III. J. Holotrich II."" Permissions to display image requested from copyright holder, reply pending.

Species: Anthopleura handi

"""Fig. 5. Spirocysts and nematocysts of *Anthopleura handi*. A-spirocyst; B, D, F-basitrichs; C-atrich; E-microbasic p-mastigophore. (Nomarski interference contrast.)"" Permission to display images granted by the University of San Francisco."

Species: Anthopleura chinensis

"""Fig. 3. Nematocyst signature of *Anthopleura chinensis* sp.nov. Tentacles: a, spirocyst; b, basitrich. Marginal spherules: c, basitrich; d, atrich; e, heterotrich. Column: f, basitrich; g, heterotrich. Actinopharynx: h-i, basitrichs; j, microbasic amastigophore A. Filament: k-l, basitrichs; m, microbasic p-mastigophore B1a; n, microbasic amastigophore A. Scale (a-n) = 10 µm."" Reprinted with permission of Hong Kong University Press."

Fig. 1. Exploded holotrich of Diadumene cincta.
Fig. 2. Unexploded holotrich of Sideractis glacialis.
Fig. 3. Unexploded atrich of Protanthea simplex.
Fig. 4. Exploded atrich of Protanthea simplex.
Fig. 5. Unexploded basitrich of Actinostephanus haeckeli.
Fig. 6. Exploded basitrich of Actinostephanus haeckeli.
Fig. 7. Unexploded microbasic amastigophor of Sagartiomorphe carlgreni.
Fig. 8. Exploded microbasic amastigophor of Protanthea simplex.
Fig. 9. Unexploded macrobasic amastigophor of Alicia beebei.
Fig. 10. Unexploded microbasic p-mastigophor of Halcampoides purpurea.
Fig. 11. Exploded microbasic p-mastigophor of Halcampoides purpurea.
Fig. 12. Unexploded, hoplotelic microbasic p-mastigophor of Metarhodactis boninensis.
Fig. 13. Exploded microbasic b-mastigophor of Stomphia coccinea.
Fig. 14. Unexploded hoplotelic microbasic b-mastigophor of Edwardsia longicornis.
Fig. 15. Exploded, hoplotelic microbasic b-mastigophor of Edwardsia longicornis.