THE PAEASITIC ANEMONE. 115 



on some univalve shell, which is tenanted by a Soldier-crab : 

 young specimens on Turritella terebra, Trochus magus, T. 

 ziziphinus, &c. ; but adults, which are much more frequently 

 met with than the young, almost invariably on the great 

 Whelk (Buccinum undatum). The dredge, indeed, often 

 brings up shells invested by this Anemone, which are 

 empty ; but I believe that in every such case the shell 

 has recently been vacated by the Soldier, and that the 

 Sagartia never voluntarily selects either an empty shell, 

 or one tenanted by the living Mollusk, for his residence. 



My friend, Dr. E. Percival Wright of Dublin, has 

 favoured me with a humorous sketch of the ways of this" 

 loving pair, — Crab and Zoophyte, Arcades ambo, — which 

 bears on the matter before us. " The following scene," 

 he observes, " was witnessed by my much lamented friend 

 Dr. R. Ball. One of the specimens referred to, attached 

 to the shell of a Buccinum undatum, which had from its 

 appearance been, in all probability, just deserted by a 

 Pag urns , was placed in a glass aquarium : in a short time 

 the Anemone left the Buccinum, and attached itself to the 

 side of the tank ; it next deserted thi3 position and fixed 

 itself on the side of a large stone that filled the centre 

 part of the aquarium. After the lapse of some weeks, a 

 Hermit Crab was dropped into the tank (I think Pag. 

 bernhardus). Well, if these Hermits can't live without 

 hiding themselves in the deserted shell of some poor Mol- 

 lusk, I think it is equally true that they can't live happy 

 until they hide both themselves and their shells in some 

 quiet little hole in the rock -work of our aquaria, from 

 whence they can look out ; and, thinking that the supers- 

 imposed stone-work adds vastly to the strength of their 

 fortifications, experience sundry intense feelings of safety. 

 Be this as it may, the Hermit in question was not long ere 

 he walked up to a little grotto that was in the rock-work 



12 



