G. ADEONA. 
237 
in the preserved specimens brought to Europe no rind 
has been discerned, yet it is by no means certain that 
when fresh, and in a living state, they do not possess a 
rind. Supposing that these beings do not change by 
desiccation, we must admit that Australasia, in these 
Polypidoms, offers us a new example of organised be- 
ings which have no place in our classifications, a cir- 
cumstance not rare in that fifth division of the world. 
The difference between the fan-formed expansion and 
the stem is so great, that naturalists at first sight 
were tempted to look upon these two parts as distinct 
beings ; it is however easy to prove that they belong 
to the same animal. Peron, who had seen them in 
the very site of their growth, told me he had frequently 
convinced himself that they were one and the same 
Polypidom. If the base of the fan-formed expan- 
sion of the Adeonas be attentively observed, it may 
be seen to extend itself into the stem,, and only by de- 
grees to change its nature : when that change is com- 
pleted in the stony articulations, we find this same 
stony substance forming the expansion, which differs 
only from the articulations in possessing cells that 
are not found in the stem. These circumstances are 
sufficient to prove that the stem and the expansion 
of the Adeonas, notwithstanding the disparity of their 
form, cannot be the productions of different ani- 
mals. 
The stem of this Polypidom is irregularly cylin- 
drical, sometimes branching, and composed of calca- 
reous articulations without pores or cells, as hard as 
coral, and separated from each other by disks or 
plates of a horny, fibrous, and flexible substance. The 
