SEA-ANEMONES AND THEIR ALLIES. 73 



only. Often they are found under overhanging rocks or in 

 deep and dark rock crevices, but on the Firth of Forth, on 

 the other hand, I have found numerous specimens growing 

 fully exposed to view on loose stones on the shore. In this, 

 as in many other cases, we require more evidence before we 

 can determine what it is that renders a locality suited to the 



Fia. 26. The plumose anemone (Actinoldba dianthus). Note the "parapet " 

 or ridge, beneath the frilled disc. After Tugwell. 



needs of the species ; it may be a protection against violent 

 wave-action which is necessary, or the abundance of some 

 particular kind of food, or a constant supply of pure water, 

 or some other unknown environmental condition. Certain 

 it is that this is a local anemone, abundant where it occurs, 

 but often absent from apparently suitable spots. It is also 

 very variable in colour, being sometimes white, sometimes 

 yellow, sometimes flesh-coloured. The fact that all three 

 colour varieties may occur in the same situation seems 



