• Norwegian: eremittkrepshydroide


Hydroid stage: The snail fur forms a 3 mm horny mat with 1-2 mm spines. The polyps may grow to a height of 13 mm. There are four types of polyps:

  • The club shaped hydranths have two circles of tentacles, with eight tentacles in each.
  • Female and male gonozooids are shorter and have fewer tentacles. The gonozooids spawn planula (free-swimming) larvae. These detect detect moving shells and attach themselves to them.
  • The dactylozooids are long threadlike individuals.

Medusa stage: No information.


This tiny hydroid may occasionally be found on rocky substrate, but is more common on shells inhabited by hermit crabs or on the shell of the common whelk.


This hydroid is well known along the European coasts, from the Mediterranean to the Arctic.