XX 
infinitely brighter while the polypi were in life ; it is 
however not impossible that, like many of the marine 
Floridas, some of these animal productions may as- 
sume more varied and brilliant hues from the com- 
bined effect of light, humidity, and their first step 
towards decomposition. 
These general considerations on Polypidoms are 
not applicable to the Polypi ; these latter are some- 
times of the clearest transparency, at others this trans- 
parency is clouded and whitish ; frequently they par- 
take of the colour of the animated mass to which they 
belong, only differing in shades according to the dif- 
ferent parts of organization. In many of the Gor- 
gonias and in some Alcyonias the colour of the Po- 
lypi is entirely different from that of the Polypidom, 
and forms an agreeable contrast. In general their 
brilliancy and transparency become tarnished and 
opaque, as soon as deprived of life, or exposed 
to the influence of the air. 
SIZE. 
With respect to size, we find Polypidoms so small 
that it requires the aid of glasses to distinguish them, 
whilst others are as elevated as the mountains : their 
base fixed on the foundation of the sea, to a depth 
that cannot be measured, whilst their extremities are 
