496 Mr.Srurcusury on the Growth of young Corals 
quoted from Rumphius, in regard to the animal of F. agarici- 
formis.  **'The more elevated folds or plaits have borders like 
the denticulated edges of needlework lace; these are covered 
with innumerable oblong vesicles formed of a gelatinous sub- 
stance, which appear alive under water, and may be observed 
to move like an insect." | 
I observed these radiating folds of the animal, which secrete 
the lamellz, and which shrink between them when the animal 
contracts itself on being disturbed. They are constantly moving 
in tremulous undulations; but the vesicles above described ap- 
peared to me to be air-vessels, placed along the edges of the 
folds ; and it is some confirmation of this opinion, that the vesi- 
cles disappeared when the animal was touched. 
'This arrangement of air-vessels would very materially assist 
in keeping uppermost the convex disc of the coral, and be of 
vital importance to the young polype at the time of separation, 
and subsequently, in keeping it upon the surface of its sandy 
bed: or if they were moved by a sudden roll of the sea, which 
would lift even the most ponderous, and possibly convey them 
a considerable distance, they would be again deposited in their 
natural position. 
That they have no power of turning themselves I proved 
during a sojourn of six weeks at Tahiti, by placing a healthy 
specimen with its upper surface downwards, during which time 
it remained in the position placed, and the vitality of the points 
of contact with the rock upon which it was laid, was destroyed. 
In Fungia limacina I have seen instances where the coral, 
having been accidentally placed, and permanently fixed in such 
unusual positions, has adapted itself to its new situation, by 
increasing upon its edges and forming a new convex surface. 
Since writing the preceding, it has been pointed out to me 
that in April 1828, some months after my arrival in England 
with 
