PLATE 1 



Frontispiece] [Photo by Culli/ord, Aberystwyth. 



Colonies of the Tube-Worm (Sabellaria alveolata) at Borth. 



Upon the tube-masses occurs the dog-whelk (Purpura lapillus). The colonies form 

 grottos in which a number of animals, notably Actinia equina, are able to shelter. 



