30 A NATURAL HISTORY OF THE SEAS 



of retractile tentacles varies in number from a few score 

 to many thousands according to species and they are 

 constantly employed to seize and convey food to the 

 stomach cavity which constitutes the bulk of the cylindrical 

 body. Multiplication is effected by means of eggs, 

 budding off, or even as the result of mutilation. Some 

 species if cut in fragments give rise to as many new 

 individuals. 



A large number of species are found in our own waters, 

 and their ways of life are infinite. The majority anchor 

 themselves to rocks, whilst a few, like the Dahlia Anemone 

 {Telia crassicornis) and the Sand Anemones, attach them- 

 selves to shell fragments buried some distance in sand or 

 gravel, the crown of tentacles showing just at the surface 

 when the animal is searching for prey. The Opelet 

 Anemone {Ammonia sulcata), one of our commonest 

 native species, often chooses such unstable anchorage as 

 the fronds of seaweeds. 



Anemones are of little direct economic value to man, 

 though the Dahlia is sometimes eaten on the Continent, 

 and on our own northern coasts is in demand as bait for 

 long lines. 



A highly interesting feature of the group is the extent 

 to which many species are found in peaceable association 

 with widely different creatures. Our own shores provide 

 two notable examples. The common Parasitic Anemone 

 {Sagartia parasitica) is a large species invariably found 

 attached to shells tenanted by the common hermit crab. 

 There is little doubt that the crab derives direct benefit 

 from its cumbersome messmates — for three or more 

 anemones sometimes attach themselves to a single shell. 



