I1O THE WORLD OF. THE SEA. 
was soft in the water, and that it became hard on exposure to 
the air— 
‘*Sic et coralium, quo primum contigit auras 
Tempore, durescit.”—OvID. 
The polypes, at least those which build the most common of 
the polypiers, are composed of a tubular body, enclosed in a 
cortical cell. That part which appears beyond the walls of this 
cell is cylindrical, and is crowned by eight little arms, which spread 
themselves out like the petals of a flower. These arms are flat, 
and wide at the base, but gradually tapering to a point. The 
edges are furnished with short, hollow barbs. When expanded, 
they are exactly like a beautiful white and semi-transparent flower, 
A RED CORAL POLYPE, 
having eight petals fixed upon a mammal bud; when closed, they 
have the appearance of an urn. Count Marsigli, who has fre- 
quently seen these creatures, says :—‘ These flowers fold them- 
selves into their cells when they are taken from the water, and 
become yellow as they decompose.” Thus the coral is, as we 
have said, externally an animal, internally a rock. 
M. Lacaze-Duthiers has recently studied the reproduction of 
the coral polype, and he has brought to light most interesting 
facts. From this clever naturalist we learn that the members of 
a coral association are either males, females, or hermaphrodites. 
Ordinarily the greater number of polypes on one branch are of 
the same sex; one branch containing almost exclusively males, 
another females; the hermaphrodites are the least numerous. 
We find in the vegetable kingdom plants which afford a similar 
