IV THE COLOURS AND PIGMENTS OF CCELENTERA 87 
tufts of fine, brightly-coloured moss, or, yet more 
appropriately, certain varieties of the very finely 
divided leaves of cultivated parsley.” So also one 
of the species of mushroom coral, Fungia crassiten- 
taculata , when in the fully extended condition, “ bears 
a considerable resemblance to a crowded growth of 
the common green seaweed, Enteromorpha .” There 
is, however, great colour-variation in the species, and 
it is only the green variety which presents this 
appearance. Finally, we may mention the case of 
the “ lettuce-corals ” ( Tridacophyllia ), which, especially 
in the green species, are said to closely resemble in 
their peculiar method of growth leaves of lettuce or 
endive. This is an interesting case of resemblance, 
for it would require an exceedingly enterprising 
biologist to construe it as a case of protective or 
alluring coloration. 
The Effect of Light upon the Develop¬ 
ment of Pigment 
On this subject there are a few interesting observa¬ 
tions. Mr. Saville Kent observed that in Euphyllia 
glabrescens the tentacles were frequently green or brown 
with paler tips, but where they were completely shaded 
from the light they were quite transparent and 
colourless with faintly tinted tips. Similarly, forms 
like Symphyllio which only unfold their tentacles at 
night, have these transparent or colourless, while the 
exposed parts are coloured with the usual brown or 
green pigments. As a curious exception to this rule 
he found that a species of Dendrophyllia, D. coccinea , 
was always coloured a bright red, even when shaded. 
