SEA- ANEMONES. 115 



paneled disc could not rest at angles with the vertical edge 

 of the aperture, the Adamsia forms an incurved ledge, or 

 bent extension of the edge, of a horny substance secreted 

 by itself, thus making its own bridge and passing over it 

 at the same time, — a very surprising instance of instinctive 

 adaptation of a creature to its circumstances, which will be 

 made further interesting when we find that there is another 

 creature, whose convenience is greatly cared for in the ar- 

 rangement. The shell thus enlarged in volume, but de- 

 creased in its opening by the Adamsia and its horny ledge, 

 forms a most happily contrived case for the dwelling of a 

 Hermit Crab, Fagurus Prideanxii. These two tenants of 

 the old deserted mansion are generally found in company, 

 and probably contribute to the supply of each other^s wants. 

 The Hermit supplies the deficiency of locomotive power in 

 the Anemone, by travelling about in search of food for 

 liimself. Small fraguients of his food may also fall to the 

 share of his humble house constructor; and it sometimes 

 happens that, a large morsel being seized by the latter when 

 the former is in want, the Hermit, acting upon the prin- 

 ciple that " might is right,^^ may compel his weaker com- 

 panion to divide the spoil. Adamsia is generally of a red- 

 dish-brown colour, becoming pale and cream-coloured near 



