722 PHILOSOPHICAL TRANSACTIONS. [aNNO I776, 



Philos. Trans., vol. 48, p. 504 ; but experience has since fully convinced me of 

 the contrary : for on the strictest examination with the microscope, of the in- 

 ternal horny parts of several of those gorgoniae fresh from the sea, and imme- 

 diately preserved in spirits, not the least appearance of tubes within the horny 

 part can be discerned, either in the longitudinal or transverse sections. There 

 is indeed a regular cannulated appearance on the surface ; but this seems to be 

 only an external moulding, and not formed by a series of longitudinal tubes with 

 interstices, as in plants ; nor is it difficult to explain whence such a moulding 

 may arise. I have observed, that the inner surface of the fleshy part contiguous 

 to the bony or horny part, is furnished with longitudinal parallel tubes, which 

 through certain pores supply the osseous matter ; this, being soft at first, and 

 only afterwards becoming hard, so as necessarily to take the form of the concave 

 surface by which it is closely pressed, and therefore assumes a striated appearance. 

 This is plainly seen in fig. 2, a, where the ends of the tubes and the striated 

 appearance on the gorgonia flabellum are expressed ; and at fig. 2, b, two of 

 them are magnified. 



In the isis hippuris, or black and white jointed coral, which is very 

 nearly a-kin to this genus, these tubes are still more clearly to be seen, as they 

 are larger, and the channels much deeper ; see fig. 3, where a is a part of the 

 coral of its natural size ; b is an extremity of one of the branches magnified, 

 with the bony part laid bare ; c a part of the same, with the bony part taken 

 out, to show the tubes with their internal orifices, through which the osseous 

 juice is supposed to exude, and form the layers of the bony and horny part. 

 This formation of the hard part, or bone of the stem, seems to be a principal 

 use of the longitudinal tubes ; but they have another also, of great consequence 

 in the growth of the gorgonia : for it is by means of these, that the animal 

 spreads itself downwards over the substances which serve for its basis, thence 

 deriving a firmness proportioned to its bulk. By means of these likewise it re- 

 pairs any deficiencies arising either from accident or natural decay, by which the 

 life of the whole would be endangered. At fig. 2, c, d, the broken stem in the 

 gorgonia flabellum is strengthened and made firm by the lateral reticulations 

 being covered over with the horny substance by means of these fleshy tubes and 

 polype suckers. This is very different from any natural repairs of broken or 

 wounded branches in trees. Besides, these tubes extend themselves any way, 

 creeping over every substance which may serve for their support and preservation 

 of the animal, throwing out the horny or osseous juice to make the whole tex- 

 ture firmer. This wonderful contrivance of nature is certainly instinct in this 

 low order of animals. To give a better idea of this kind of instinct, and to 

 show in what it differs from what is called radication in plants, with which some 

 people, for want of better information, are apt to confound it, I have given a 



