Hermit-crab & companion

The Cloak-anemone lives on the shell of the Hermit-crab, that formerly was inhabited by the Whelk
De Mantelanemoon  woont op de schelp van de Hermietkrab, waarin voorheen de Wulk woonde.

Watercolour of Hermit-crab, based on Gosse, 1865: Pl. 27 .
The Cloaklet is based on the late version of Blaschka glass model 33,
Adamsia palliata - the Cloaklet.
(ca. 15x20 cm, 2011) 

"It is that unaccounted association of diverse and unrelated creatures, which, if we had not repeatedly seen it, we should not believe; the companionship of the Hermit-crab with the beautiful Cloak-anemone. … 
The companion of the Cloaklet … is exclusively a deep-water species. Found on various parts of our coast, it invariably occurs in this association. I believe the Crab in no instance lives without the Anemone, the Anemone in no instance without the Crab. Examples, indeed, do now and then occur, as mentioned by Forbes in which the one comes up in the dredge without the other; but I believe this is only when the rude action of the dredge has frightened the crab, and induced it suddenly to vacate the shell and desert its friend."
(Gosse, 1865, p. 237-238)

Litt.:  Philip Henry Gosse. A year at the shore;  London : Strahan, 1865.