196 
CLASS III.— ORDER II. 
temperature, they mistook these little animals for the 
blossoms of marine vegetation. This error continued 
many years after the discovery of Pcyssonnel, a dis- 
covery which was forgotten till Trembley’s observa- 
tions on the fresh-water polypi brought to the recol- 
lection of many members of the Academy of Sciences 
the marine Polypi of Peyssonnel ; and, thanks to the 
investigations of Bernard de Jusias and of Guettard, 
the true nature of the Gorgonias, as well as that of 
other Polypidoms, remained no longer doubtful. 
Since this period Linneus, Ellis, Pallas, Cavolini, 
Spallanzani, Bose, and other learned men, have studied 
the polypi of the Gorgonias, and have given us the 
result of their observations ; but their discoveries have 
not yet dispelled our ignorance respecting their manner 
of existence, or the nature of their internal organi- 
sation. 
All the species of Gorgonias are attached to rocks 
and other marine bodies by a more or less extended 
base, whose surface is usually deprived of the fleshy 
substance which covers the other parts of the Polypi- 
dom. From this base arises a stem, which gradually 
diminishes in thickness up to the smallest branches, 
the extremities of which are often setaceous. The 
branches vary much in their form and respective si- 
tuation ; they are either dispersed or spring regularly 
from the sides, sometimes they are found growing 
double, and at others regularly pinnated ; some are 
flexible, some straight, some curved, some single, and 
some anastomosed ; in short, some are found slightly 
compressed, some nearly flat, and some angular or 
three sided, but the greater number are cylindrical. 
