448 POLYPI, 
In the third tribe, or the 
NATANTES, 
The axis is stony but not fixed. 
PENNATULA, Lin.; 
A common body, free from all adhesion*, of a regular and constant 
form, and susceptible of locomotion by the contractions of its fleshy 
portion and the combined action of its Pclypi. ‘This body is fleshy, 
and contracts or dilates in its various parts by means of the fibrous 
layers that enter into its composition ; its axis encloses a simple stony 
stem; the Polypi have generally eight dentated arms. 
Most of the species diffuse a vivid phosphorescent light. 
Whatever be the general fcrm of the Pennatulz, one of their ex- 
tremities is always desfitute of Polypi, and has been compared to the 
tubular portion of a bird’s feather. 
PrennatTuba, Cuv. 
The Pennatule, properly so called, have given their name to the 
whole genus, which name has been derived from their own resem- 
blance to a quill. The portion destitute of Polypi is cylindrical and 
terminates in an obtuse point. The other part is furnished on each 
side with wings or lamina, more or less long and broad, supported 
by spines or rigid sete which arise from their interior and roughen 
one of their edges, without, however, being articulated with the 
stony stem of the axis; it is from between their lamine that the 
Polypi protrude. 
P. rubra, P. phosphorea, Gm.+; Albinus, Annot. Acad., I, 
vi, 3,4. Where the stem between the laminz is extremely 
‘scabrous posteriorly, with the exception of a longitudinal line. 
In the Atlantic ocean and Mediterranean. 
P. grisea, Gm.; Albinus, Annot. Acad., I, vi, 1,2. Larger, 
with broader and more spinous lamine; stem smooth. More 
particularly in the Mediterranean f. 
Vireuxaria, Lam. 
The Virgulariz only differ from the Pennatule in their wings, 
which, much shorter in proportion to their total length, are destitute 
of spines §. 
These wings sometimes merely represent transversal ranges of 
tubercles||.. In 
little importance, see the ‘‘ Exposition Methodique des genres des Polypiers, avec les 
planches de Solander et Ellis,’? by Lamouroux. Paris, 1821. 
* Certain species penetrate into the sand or become entangled in the folds of va- 
rious marine bodies, but never form any durable adhesion. 
+ Both are red. The P. rubra only differs from the other in having a little spine 
at the base of each posterior Jamina. It is perhaps a mere variety. 
+ Add Pennatula argentea, Sol. and Ell., Zooph., VIII, 1, 2, 3;—P. grandis. 
§ Pennatula mirabilis, Mull., Zool. Dan., XI, very different from the true Pennat. 
mirabilis of Linnzus. 
|| Pennatula juncea, Pall. and Gm.; also very different from the P. mirabilis, L. 
The Virgulaire australe, Lam., does not differ from the juncea, 
