1012 Marvels of the Universe 
Although corals continue their species 
often by ova, they as frequently extend 
their colonies by means of fission, or even 
by budding. The method known as fission 
is responsible for many of the varied shapes 
which their skeletons exhibit. In the 
Mussa, we find that by the splitting-up of 
the individuals, others have been formed 
side by side with the founders of the colony, 
and the hard skeletons have consequently 
remained attached to one another. In a 
further development a number of tortuous 
skeletons have been formed, all still united 
to the parent stalk, but leaving between 
Photo by] ie them channels as tortuous as the coralla. 
BRAINSTONE CORAL. The result is seen in the coral known as 
The labyrinth-like form of this beautiful Coral is due to the way in the Ewphyllia, which we illustrate (pages 
which the polyps have branched and extended by budding. 7 aa ee : 
ToIo and torr. Somewhat similar in build, 
but with the process carried still further, we have the Trachyphylliia, shown on each side of the 
photograph on page torr. But in others the rows of corallites tend to become united at their 
bases more rapidly than in others, and when they grow outward at their sides as quickly as they 
grow upward, they become massive, and we have the form known as the Brainstone Coral (here 
shown). In such forms the combined corallites wind in a complex manner over the whole ‘mass, 
and at once suggest the convolutions of the human brain. In other corals we find that the greater 
growth is in a vertical direction, and then we have the Dendyophyllia, in appearance like a living tree ; 
or the Isis, whose skeleton is made up 
of alternate pieces of horny and cal- 
careous material ; or the madrepores, and 
the millepores, popularly known as “ Stag’s 
Horn Coral.” We have called any of these 
anemone-like creatures by the name of 
coral if they formed a hard limy skeleton ; 
but it must be remembered that in the 
millepores, the pink Stylaster, and the 
brick-red Distichophora, there are certain 
differences of organization which separate 
them somewhat from the true corals, 
and ally them with the little green Hydra 
of our ponds and ditches. They are, 
therefore, sometimes called “ hydrocoral- 
lines.” 
~ We have mentioned the madrepores, 
and in this family we have a very large 
number of species Their structure is 
perhaps the most familiar of all the corals, 
ce Sk save the precious red. coral. 
HD DE ure ges Many of the names of corals terminate 
MADREPORE. : tact 
in the syllable “ pore,” and it is interest- 
A section cut lengthwise through a small branch of Coral, much 
enlarged to show the tubes into which the polyps withdraw. ing to consider why this is SO. We know 
