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imaginings; and to have seen how many of the very finest 
passages in our literature have been given to the description and 
elucidation of the painters’ art. We might have gone over the 
roll of painters who have sung and of poets who have painted, 
but all this must be omitted. I have, however, I hope, succeeded 
in making a little clearer the real limits and aims of the two 
sister arts—each noble in itself and helpful to the general 
culture of human life and the amelioration of its somewhat hard 
conditions. 
CORALS. 
By A. E. TOVEY, D.Sc. October 7th, 1884. 
Corals are formed by animals, called polyps, the most 
important of which are nearly identical in structure with our 
common sea anemones. The polyps are more or less cylindrical 
in shape, one end of the cylinder being closed, and generally 
fixed; the other end being free, having a anil i its centre, and 
being fringed with one or more circle of tentacles. The mouth 
leads into a sac, which opens below into the general body-cavity. 
This body-cavity is divided into compartments by partitions 
mesenteries) which radiate from the wall of the sac to that of 
the body. The body-cavity is continued into the tentacles, which 
are generally perforated at their extremities. The body wall is 
composed of three layers: the exterior layer, or ectoderm, which 
is continued over the oral surface, and lines the gastric sac, being 
formed of somewhat cylindrical cells interspersed with cells 
supposed to be tactile, and with other cells containing 
introverted threads, used in the capture of its prey, hence 
-ealled thread-cells; a middle layer, or mesoderm, consisting 
of longitudinal and transverse layers of contractile fibres, by 
which the movements of the polyp are effected; and a layer, 
called the endoderm, which lines the body-cavity, consisting 
of nutritive and reproductive cells. The polyps increase by 
budding; by fission, i.e., a large polyp dividing longitudinally 
into two; and by sexual reproduction, when the ovum gives rise 
to a free swimming ciliated oval embryo, which developes mouth, 
-mesenteries, gastric sac, &c. The coral is a calcareous skeleton 
which makes its first appearance as a radiating series of plates 
in the mesoderm of the base of the polyp; a calcareous ring is 
then developed exterior to the plates, which finally coalesce 
with it. As the polyp grows in length, the coral also increases 
in length, and as the exterior ring is generally the furthest 
advanced part of the coral, a sort of cup or calycle is formed at 
