ETJPAGURUS. 563 



of the proceeding in his quaint " Year at the Sea-side,"* 

 The crab and the Adamsia are never found separated 

 from one another, and their mutual companionship 

 seems necessary for their existence. 



A similar but even more remarkable case of 

 commensalism is that recorded by Alcockf between 

 Chlaenopagurust and a compound colony of Zoantharian 

 polyps. The Actinian settles directly on the abdomen 

 of its host, and grows over it imbedded in a copious 

 fleshy coenosarc which the crab can draw over its head 

 or throw back at will. There is no intermediate 

 structure, such as the molluscan shell of E. prideauxii, 

 to introduce the two forms. The crab simply pulls the 

 coenosarc over its back like a cloak, and keeps it in 

 position with his claws — "the polyps seeming to have 

 no power of adhesion." 



A nearer approach to the method adopted by 



Adamsia is seen in Parapagurus pilosimanus, which 



lives in the cavity in the coenosarc of a large 



Epizoanthus which had settled originally on the shell 



of the hermit crab, but had absorbed it on growing up. 



Other associations with Actinians are seen in Pagurus 



striatus and E. excavatus with the anemone Sagartia 



parasitica. P. striatus plants the anemone (which 



however, is independent of the association for its 



existence) on its shell in much the same fashion as 



E. prideauxii does the Adamsia, i.e., by means of its 



chelae. The two species are often found living separately, 



and P. striatus does not confine its attention strictly to 



Sagartia. 



* An interesting but highly coloured note on the habits of 

 this pair by Stuart Wortley may be found in Ann. & Mag. Nat. Hist. 

 ser 3. XII. p. 388, 1863. 



t Journ. Asiatic Soc. Bengal. Pt. II., No. 2, 1899. 



J This species is now included in Henderson's Paguropsis. 



