CCELENTERATA. 
251 
long-lived compared with the Hydrozoa, living for several 
years. One kept in an aquarium in England is now more 
than sixty years old. 
1. Soft-bodied Polyps.—The best-known representative 
of this group is the Actinia (Metridium), or Sea-anemone. 
It usually leads a solitary life, though frequently several 
are found together, some of which have arisen as buds from 
the others. It is capable of a slow locomotion. Muscular 
fibres run around the body, and others cross these at right 
angles. The tentacles, which often number over two hun¬ 
dred, and the partitions, which are in reality double, are in 
multiples of six. At night, or when alarmed, the tentacles 
are drawn in, and the aperture firmly closed, so that the ani¬ 
mal looks like a rounded lump of fleshy substance plastered 
on the rock. It feeds on crabs and Mollusks. It abounds 
on every shore, especially of tropical seas. The size varies 
from one eighth of an inch to a foot in diameter. 
2. Coral Polyps.-—The majority of Anthozoa secrete 
a calcareous or horny framework called “ corah 55 With 
few exceptions, they are fixed 
and composite, living in colonies 
formed by a continuous process 
of budding. Their structures take 
a variety of shapes: often dome¬ 
like, but often resembling shrub¬ 
bery and clusters of leaves. The 
members of a coral community 
are organically connected; each 
feeds himself, yet is not indepen¬ 
dent of the rest. We can speak 
of the individual Corals, a, c, 
but we must write them down 
dbc . The compound mass is “like Fig. 200.—organ-pipe 
■»» . •) , 0 i , pora musica). Iudian Ocean. 
a living sheet of animal matter, 
fed and nourished by numerous mouths and as many 
stomachs.” Life and death go on together, the old 
