SUPPLEMENT 
THE POLYPI. 
In the fourth class of this great division, the first and most 
extraordinary animals we meet, are the ACTINIZ, vulgarly 
known by the name of sea-anemones, or fixed sea-nettles. 
Their body is fleshy, very contractile, usually remaining fixed 
upon its base, but able, however, to change place, either by 
crawling on this same base, or walking upon this tentacula. 
When the body of the actinia is the most contracted, it re- 
presents a hemisphere, with a small aperture at its summit. 
Such is the position which these animals retain, when they 
are stranded, or when the sea is troubled and the sky over- 
cast. But when they are hungry, or the weather is fine, 
they expand and blossom. The small aperture then be- 
comes as broad as the base, and the body represents a 
short cylinder. The mouth is at the centre of the supe- 
rior base of the cylinder, and the whole circumference is 
furnished with several ranges of tentacula, which represent 
extremely well in their fine colours and arrangement, the 
petals of certain double flowers. ‘The mouth conducts into 
the stomach, which is a sac wrinkled internally, but without 
any other issue, at least visible, except the mouth. The in- 
