230 HISTOEY OF BRITISH ZOOPHYTES. 



Actinia, and that its formation presents a striking instance 

 of the operation of that beautiful law of Nature which 

 makes the habits of one animal subservient to the wants of 

 another." I may insert the following, which Dr. Johnston 

 is pleased to quote at this place from my ' Excursions to the 

 Island of Arran :' " Many naturalists have observed that 

 there seems to be a treaty of union betwixt the hermit-crab 

 and the spotted sea-anemone. I lately kept one of these 

 pretty creatures for some days in sea-water ; it had fastened 

 itself to a little fragment of a screw-shell (Turritella terebra), 

 but its co-tenant in the inside was not a hermit-crab, but a 

 pretty red annelide. Be this as it may, certain it is that 

 on this occasion we found that the spotted anemone had 

 fastened itself to the outer lip of many of the roaring 

 Imckies (Buccinum undatum] brought up by the dredge, and 

 whenever there was an anemone without, there we found 

 a hermit-crab within. In all likelihood they in various 

 ways aid each other. The hermit has strong claws, and 

 while he is feasting on the prey he has caught, many spare 

 crumbs may fall to the share of his gentle-looking com- 

 panion. But soft and gentle-looking though the Actinia 

 be, she has a hundred hands, and woe to the wandering 

 wight who comes within the reach of one of them, for all 



