82 CORAL FORMATIONS. 
coral—will come under consideration. ‘The species here referred to 
are called Actini@ in science, in allusion to the radiated or aster-like 
flower which forms the summit of the animal.* There is the same 
allusion in the common appellation Sea-anemone. The richest ane- 
mones, daisies and tulips of our gardens would not rival them in 
beauty, neither will they exceed them in the size of their flowers; for 
a breadth of two and three inches is common. ‘The polyps here 
alluded to, along with the coral polyps allied, constitute the order or 
division of zoophytes called AcTINOIDEA.t+ 
The Actiniz are entirely fleshy, and usually live attached by their 
lower extremity to the submerged rocks of the shores. The mouth, 
at the centre of the flower-like disk forming the summit of the ani- 
mal, is a simple opening without teeth or appendages of any kind. 
The tentacles—the petals of the flower—are tubular organs, and com- 
municate internally with the interior cavity of the animal. The 
animal contracts, when disturbed, and conceals the flower by rolling 
inward over it the margin bearing the tentacles ; and in this state it 
seems like a lifeless lump of animal matter. Left quiet for a while it 
again expands and appears as before. This expansion is produced 
by receiving water into the interior from without, mostly through the 
mouth, and thus filling the tentacles and swelling out its fleshy body. 
They are generally found expanded with the mouth wide open to 
receive their prey. As they are fixed to the rocks, they must wait 
for their food to come to them. When a crab, shell-fish, or anything 
alive, within the capabilities of their bodies, comes within reach, they 
usually secure it by closing upon the victim the tentacles, (which often 
have a stinging power,) and pushing it into the mouth. In many 
species the tentacles are too short to aid in capturing food; and they 
can then subserve only the purpose of aerating the blood, a function 
in which all parts of the body are more or less concerned. 
The interior of the actinia contains a cylindrical stomach suspended 
from the disk, which opens at bottom into the general cavity of the 
body. ‘This general cavity, below the stomach and around it, is 
divided into compartments by radiating fleshy lamelle, the larger of 
which in their upper part connect the stomach with the sides of the 
animal. The most important function of these lamelle is that of re- 
production, some being spermatic, and the others bearing clusters of 
ova. These ova leave the body by passing out through the stomach 
* From axriwv, a ray of the sun, 
+ This term alludes to their general resemblance to Actiniz. 
