IV THE COLOURS AND PIGMENTS OF CCELENTERA 83 
Although descriptions of coloured organisms do 
not as a rule convey much idea of their beauty, it may 
illustrate the problem before us if we give details of 
some of the corals studied by Mr. Saville Kent during 
his sojourn at the Barrier Reef. It is perhaps not 
unnecessary to repeat that one must read into the 
list of tints something of that purity of colour, that 
varying light and shade, which have made the glories 
of spring and autumn a never - failing source of 
artistic inspiration. 
The Colours of Corals and Sea-Anemones 
Among the masses of coral which go to form the 
reef, the different species of Madrepora, or stag’s 
horn coral, are usually very conspicuous. In this 
country specimens of Madrepora are quite familiar 
as slender branching stems studded with tiny 
openings, but they reach us always in the white or 
bleached condition ; in their natural condition almost 
all are brightly coloured. Thus in one species 
(M. prostrata) the whole colony is usually bronze- 
green with yellow tips, but it may be bright green 
with yellow tips, or more rarely shrimp-pink with 
yellow tips. Again, another species is remarkable 
in having the ends of its branches crowned by 
larger cells than those which constitute the branches 
themselves. In this case the branches are pale 
yellow to white, the polypes being light brown to 
greenish-yellow; the large terminal cells are a 
delicate china or bright turquoise blue, their con¬ 
tained polypes being of an emerald - green tint. 
Another species, M. hebes , shows a large amount of 
