101 



sensation, as if its surface were beset with innumerable minute -asperities,, 

 a sensation which I had been accustomed to i'eel, whilst handling such 

 petrified alcyonia as had not suffered from attrition, and which ap- 

 peared not to have been deprived of their cortical part. I am there- 

 fore led to believe, that on this fossil, a considerable portion of the 

 original cortical part still remains ; but which has been entirely re- 

 moved from those which have been just described. I am also induced to 

 suppose, from the appearance of this fossil, that the surrounding rami- 

 fying filaments were disposed between the cortical part and the body 

 of the alcyonium ; and that, besides the office just attributed to them, 

 they also served to connect the cortical investing part with the included 

 spongy mass. 



The fossil, figured Plate IX. Fig. 7, appears to have been of the 

 same species, and is, in many respects, exceedingly interesting. It 

 has been imbued with silicious matter so transparent, that its highljr 

 polished transverse section displays the internal structure pi the alcy- 

 onium as plainly as it could have been discoverecHfl-fcherecent animal 

 itself. The greater art had evidently been of a spongy texture; the 

 spongy substance itself being most distinctly visible with a lens of a mo- 

 derate power. Through this substance, several interrupted lines, as the 

 figure will shew, pass in regularly disposed radii from the centre to the 

 circumference, and an examination of these with the magnifying lens, 

 gives every reason to suppose that they are distinct from each other, 

 and are transverse sections of those fibres which, passing from one part 

 of the body to the other, have, by supporting it, served to preserve its 

 form. They also have probably been fasciculi of muscular fibres, and 

 may have served, in the living animal, to have produced that alternate 

 contraction and dilatation of the external openings of this animal, 

 which we have already spoken of, and which Marsilli has observed to 

 take place in the external openings of sponges, when filled with the, 

 water, on being taken out of the sea. Another observation of this 

 same ingenious naturalist also leads to the supposition, that this coa- 



