Actiniae. 
Z. HELIANTHOIDA. 
225 
body is very sensible to external irritations : no point of the skin, 
the tentacula, nor the membrane of the stomach can be touched, but 
immediately the creature evidences its sense of the injury by contrac- 
tions and other motions of the part. They are said also to be very 
sensible of atmospherical changes : they shrink under a glare of light;* 
but in a calm and unclouded sky expand and disclose every beauty, 
while they remain contracted and veiled in cloudy or stormy weather. 
Dicquemare has even found, from several experiments, that they 
foretell changes in the weather as certainly as the barometer : when 
they remain naturally closed there is reason to fear a storm, high 
winds, and a troubled sea ; but a fair and calm season is to be antici- 
pated when they lie relaxed with spread-out tentacula. f 
Actinia. “ Nervous filaments surround the muscular foot of the Actinia, be- 
neath the stomach, and present minute ganglia in their course, from which nerves 
pass out to the circumference, and to the muscular folds which here possess 
great power of contraction. The same system probably exists in many other 
closely allied forms of polypi.” Outl. of Comp. Anat< p. 182. 
* It has been suggested that their perception of light may be communicated 
through the tentacula, on the tips of which, Bose assures us, there is a black 
point or eye . Vers, Vol. ii. p. 247. This black point, as w r ell as the other parts of 
Bose’s description of the tentacula, is wholly imaginary ; nor is there a necessity 
of an eye to explain the phenomena, for there can be “ little doubt that a dif- 
fused sensibility to light and sound exists in animals which present no special 
organs of vision or hearing.” Brit, and Foreign Med. Rev. v. p. 491. 
f Dicquemare’s observations seem of sufficient interest to justify their. insertion 
at length. He says, “ My very earliest observation showed that the sea ane - 
monies feel and prognosticate, within doors, the different changes of tempera- 
ture in the atmosphere. I had not leisure at that time to form tables of their 
various indications, but I have since done it. This fact, if applied to practice, 
might be of use in the formation of a sea-barometer, an object of no small im- 
portance, which several ingenious men have hitherto endeavoured in vain to 
furnish us with. I should prefer the anemonies of the third species for this pur- 
pose, their sensation being very quick ; they are also easily procured, and may be 
kept without nourishment. Five of them may be put in a glass vessel, four inches 
wide and as many in depth, in which they will soon cleave to the angle formed 
by the sides and the bottom. The water must be renewed every day, and as 
they do not require a great quantity of it, as much may be fetched from the sea (if 
they be kept on land) as will supply them for several days ; its settling some 
time will only improve it. If the anemonies be at any time shut or contracted, I 
have reason to apprehend an approaching storm, that is high winds, and an agitated 
sea. When they are all shut but not remarkably contracted they forebode a 
weather somewhat less boisterous, but still attended with gales and a rough sea. 
If they appear in the least open, or alternately and frequently opening and clos- 
ing, they indicate a mean state both of winds and waves. When they are quite 
open I expect tolerable fine weather and a smooth sea. And lastly, when their 
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