IOLO Marvels of the Untverse 
Photo by] ae [W. Saville Kent. 
A MADREPORE CORAL. 
In this species the polyp-tubes are large and very 
plainly seen. 
rapidly by means of a vibrating hair-like process. 
at a time when the boundary between animal 
and vegetable was not clearly defined ; whilst 
to the creatures which we are now discussing 
the poetical name of “ daughters of the sea” 
was given, for that is what the Greek words 
mean from which we derive our word “ coral.” 
The hard skeleton gives us but a poor idea of 
the wonderful appearance of these creatures 
when living, for in some of them, as in the 
case of the red coral, not even the clefts re- 
main in which the polyps were seated; these 
made no impression on the solid skeleton. In 
many others the clefts were in the “ corallum ” 
itself, and the hard part grew in the shape of 
thin plates right up inside the outer portion of 
the creatures themselves. Thus in most of 
the corals we see this arrangement of thin, 
leaf-like plates, all seemingly radiating from 
the common centre. 
The coral animal is nothing but a minia- 
ture sea-anemone. Its tentacles surround 
its mouth, and this leads down into a stomach 
and a body-cavity. Its young, strangely enough, 
are altogether unlike the parent. When an 
ovum is discharged and has been fecundated, 
it becomes a tube-like object, and swims about 
It finally settles down on a rock, and it begins 
to deposit a limy base. It develops a mouth and tentacles, and will, in course of time, become 
Photo by) (H. J. Shepstone. 
CUP CORALS. 
Though differing in form, these are constructed like 
those shown on the opposite page and are nearly related to 
them. 
an adult coral. It then gives rise to a colony 
by sending off buds and developing many 
thousands of individuals. On the other hand, 
there are some corals which, although they grow 
and grow, yet remain simple and single corals 
all their lives. Such an one is the cup-coral, 
which in times long past grew in profusion ; 
in fact, owing to the numbers in which this 
genus existed in former days, they must have 
formed what are practically great reefs of fossil 
coral. It is extremely interesting to remember 
that amongst the one or two true British corals, 
one is the unique little Devonshire cup-coral, 
which is found off Ilfracombe and elsewhere. 
The metamorphoses through which a coral 
passes are just the reverse of the familiar 
changes through which an insect passes. The 
coral is free in its larval state and fixed in 
adult life. The chrysalis of an insect is almost 
immovable, but the butterfly is as gay as the 
wind. 
