24 
force with which they clasp the lamella, on which they exert their 
plastic powers. The other ends of these round bodies terminate in 
small cylindric tubes, M'hich are attached to the shell of the animal, 
in the centre of which is seen its head, capable of moving with great 
quickness, and ornamented with several rays, which are most probably 
the arms or claws with which it seizes and secures the animalculae on 
which it feeds. 
The great number of species under the genus madrepore, and the 
near approach in many respects of these species to each other, render 
the separation of them, even in a recent state, very difficult, unless by 
the aid of perfect specimens. But when we take into consideration, the 
minuteness, as well as the extreme delicacy, of structure, of those parts, 
from which their specific and even their generic characters are deduced 
in many corals ; and, also, reflect on the vast changes which the fossil 
has undergone, and the injuries to which it may have been exposed 
through countless ages, it must be evident, that it will be frequently 
very difficult to trace the mineralized madrepore to its recent analogue. 
Many also of the recent corals are not known in a mineralized state ; 
and among the fossil corals there are also many, which cannot be 
referred to any known recent species. Under these circumstances, I 
think it necessary to apprize you, that a much less degree of correspon- 
dence will be made out between the recent and the mineral corals than 
you might have expected. 
From this, however, I trust more of gratification than of disappoint- 
ment will proceed. More of the inexhaustible riches of creation will 
be displayed ; and sufficient proofs will be found among this class of 
animals to determine, that the creative powers of nature have not been 
confined to the forming of such animals only as now exist. 
Agreeable to the arrangement of Linnaeus, we shall commence with 
the examination of the simple madrepores, those which are formed of 
a single star. 
