222 

 PRIMNOA. 



A TREE-FORMED, dichotomoiis Polypidom ; papil- 

 lous 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 of 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 (hem, which in 



