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PRIMNOA. 
A tree-formed, dichotomous Polypidom ; papiP 
Ions projections long and pyriform, or conical, pen- 
dent, imbricated, and covered with scales equally 
imbricated. 
One only species of Polypidom forms the genus 
Primnoa, which all authors have agreed in uniting 
to this Gorgonian order, but whose characteristic pe- 
culiarities are too striking to confound it with others 
of the same order. 
Many naturalists have mentioned the Primnoa 
Lepadifera, but have never noticed the polypi of this 
singular production, and all of them have taken the 
long pyriform and pendent bodies covered with im* 
bricated scales for polypean cells ; my observations 
have induced me to consider them as the polypi them- 
selves, and not their habitation. The tentacula appear 
to me to be conical, and, in a state 6f repose, seem to 
close the opening that communicates with the interior 
cavity, which is large, and without doubt destined to 
contain the organs of most importance to the exist- 
ence of the animal. The external part of the papilla 
( mamelon ) is covered with scales of the same nature, 
and of a form resembling that of the tentacula. 
The Primnoas, placed at the latter part of the order 
of Gorgonias, ought perhaps to conclude the genera 
of rind-formed or corticiferous Polypidoms, from the 
peculiar character of their polypi. These little ani- 
mals, — which in the Spongias are confounded with the 
gelatinous substance that envelopes them, which in 
