Tentacle cnidae of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria: Anthozoa)


  • Carina Östman Animal development and Genetics, Evolutionary Biology Centre (EBC), Uppsala University
  • Jens Roat Kultima Uppsala University
  • Carsten Roat Department of Ecology, Environment and Geology, Umeå University




sea anemone, nematocysts, cnidae, catch-tentacles


Tentacle cnidae of Metridium senile (Linnaeus, 1761) were examined by light microscopy. In addition to spirocysts, feeding-tentacles had 3 nematocyst categories grouped into medium and small size-classes, including 5 types. Spirocysts dominated, especially distally, followed by medium b-mastigophores. The density of cnidae decreased towards the tentacle base. Early cnidoblasts were numerous on the tentacle tip. Late cnidoblasts appeared in a moderate number on the mid-tentacle. Catch-tentacles, found in two Metridium specimens, had a maturity gradient of isorhizas and gland cells along their length. Their tip had two distinct types of mature isorhizas in great numbers and large gland cells, but lacked spirocysts. Mature isorhizas and gland cells decreased in number towards the tentacle base. On the mid-tentacle differentiating ages of isorhizas were numerous. Ordinary feeding-tentacle cnidae, abundant at the tentacle base, decreased in number distally along the tentacle.


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How to Cite

Östman C, Roat Kultima J, Roat C. Tentacle cnidae of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria: Anthozoa). Sci. mar. [Internet]. 2010Sep.30 [cited 2024Mar.3];74(3):511-2. Available from: https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/1179