296 Proceedings of Royal Society of Edinburgh. [sess. 
As the conditions under which these anemones have lived for so 
long may he of interest, the following particulars are given. The 
bottom of the bell-jar is covered with small rough stones on which 
several species of green algae are growing. On these rests the 
large stone containing the cavities in which the anemones are fixed. 
The sea- water in the jar (about four gallons) is changed every six 
or eight weeks, and is usually aerated every morning. From time 
to time a little fresh water is added to keep the density of the 
whole constant. The anemones are fed about once a month on 
small pieces of raw lean beef. They usually reject fish or mutton,* 
but appear to digest the beef very thoroughly, a small mass of 
white floeculent matter being ejected from the mouth a day or two 
after feeding. In addition, the anemones catch and feed upon the 
small isopods which abound among the algae One of us lately 
observed a specimen seize and engulf an Actinia mesembryanthemum 
which had freed itself from a neighbouring stone and come into 
contact with the tentacles of the Sagartia. Two days later the 
victim, almost intact, but quite dead, was ejected. Those tentacles 
of the captor (Sagartia) which had first touched the Actinia 
remained for some days diminished in size and opaque in colour, 
but finally recovered their usual appearance. Sagartia troglodytes 
is evidently not immune to the poison of Actinia mesembryanthemum , 
but, so far as could be ascertained, only the tentacles of the former 
suffered from the effects of the poison of the latter. Probably the 
nematocysts of the latter became inoperative soon after its capture, 
either owing to the death of the Actinia or to some other cause, so 
that the internal structures of the Sagartia remained practically 
uninjured. Grosvenor ( Proc . R.S.L. , vol. 72, 1903, pp. 478-479) 
ascribes the discharge of nematocysts to osmotic action. His 
experiments show that the contents of the capsule are able to take 
* Owing to the value of these aged specimens, we have not been able to 
make sufficient experiments upon them to determine whether they have a 
sense of taste, but the above observations seem to suggest that such a sense is 
present, though feebly developed. For an account of such experiments see 
(I. H. Parker, “The Reactions of Metridium to Food and other Substances,” 
Bull. Mus. Comp. Zool. Harvard , vol. xxix., 1896, pp. 107-13 9. Parker 
concludes that the tentacles of this anemone when stimulated with meat juice 
move so as to point to the mouth ; similar stimulation to the lips gives rise to 
peristaltic movements in the stomodseum, reversal of the ciliary action of the 
lips, and contraction of the sphincter muscle of the oral disc. 
