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force with which they clasp the lamellae, on which they exert their 

 plastic powers. The other ends of these round bodies terminate in 

 small cylindric tubes, which 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 animalcule 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 corres- 

 pondence 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. 



