74 LIFE BY THE SEASHORE. 



against the supposition that the colour variations are 

 "adaptive," or directly determined by the environment. 



As to the general characters of this anemone, notice the 

 smooth cylindrical column, with no trace of suckers, but 

 with minute pores, from which acontia may be emitted. 

 The upper margin of the column is thickened, and forms a 

 "parapet," which is separated from the frilled disc by a 

 groove or fosse. It is this frilled or puckered disc which is 

 so distinctive a character of the anemone. It is very thin, 

 and bears very numerous small tentacles, banded with white, 

 the whole appearing like the "foliated crown of a palm 

 tree." The mouth is grooved, usually has its margins highly 

 coloured, and has one, two, or three siphonoglyphes (see 

 p. 66) a very interesting range of variation, which also 

 affects the mesenteries internally, and which you should not 

 fail to notice. 



The plumose anemone lives well in captivity, and is 

 remarkably active for a sea-anemone, continually changing 

 its position, but generally keeping very close to the surface 

 of the water, where the oxygen must be most abundant. 

 Often in the course of its movements it leaves a fragment 

 of the wide base behind it, and this fragment may grow into 

 a new anemone. Both in captivity and in natural conditions 

 it has a curious habit of distending a part of the body with 

 water while the disc and tentacles are retracted, and then 

 drops in a limp and flaccid way from its point of attachment 

 a translucent shapeless mass. In the young specimens 

 the tentacles are not so numerous, and the disc is not dis- 

 tinctly frilled, but even at this stage it is hardly possible to 

 confuse it with any other anemone. 



Related to the sea-anemones are the Alcyonarians, which 

 are represented on the shore by Alcyonium digitatum, or 

 "dead men's fingers." It is a colonial form, consisting of a 

 number of small polypes embedded in a fleshy mass. After 

 death the fleshy substance is much more conspicuous than 

 the polypes, and in the condition in which it is tossed on 

 shore after storms is not a pleasing object, for there is no 

 beauty of form, and the colour is too " fleshy " to be pre- 

 possessing. In the living condition, on the other hand, with 

 its glassy polypes fully expanded in a quiet pool, it is a 

 singularly beautiful creature, and one very well worth study. 



