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room xi. are covered by a calcareous coat. The genus 
Mopsea only differs from the Isis in the bark 
being more permanent. 
The Gorgonice are easily known by the axis 
being horny and continuous, and the bark is 
persistent. In most of these the cells of the 
animals are even with the surface, as the double- 
edged Sea-Fan ( Gorgonia (triceps) ; in others, 
as the common Sea-Fan ( Gorgonia fiabellum ), 
the cells are slightly prominent. The Eunicece 
only differ from the Gorgonice in the cells being 
cup-shaped and prominent, the bark thicker, 
and the axis more slender and tubular. The 
Pleocaurce have the same thick bark as the 
Eunicece , but the cells are immersed. The 
^ Muricece and Primnoce have a rather thinner 
bark and prominent cells, covered with scales. 
The genus Antipathes has an axis like that of 
the Gorgonice , but is covered with minute spines, 
so as to be rough to the touch, and it is said, 
in its living state, to have a thick gelatinous 
bark, in which the polypes are immersed; but 
both the polypes and the bark are deciduous. 
The family of Alcyonia ( Alcyoniadce ), are 
very like the Gorgonice and the true Corals 
in the form of their polypes, living in cells 
sunk into a fleshy bark, which is attached to 
marine bodies by a dilated base; but they are 
without any distinct axis, and are strengthened 
by 
