54 



cabinet of Ingham Forster, Esq. but am unable to determine whether 

 it is not the same fossil with the last described, differing only in the 

 size of its stars. 



Madrepora arachnoides, with close, smooth, and delicate stars, the 

 rays of which are slightly waved. This fossil is figured with tolerable 

 accuracy both by Scheuchzer* and by Volkmann-f-. It appears to be 

 this fossil to which the remarks of Langius most properly apply, where 

 he observes, " aliquando stellarum loco rosas exhibent, & tune 

 rhoditce, oder roscnstein, vocantur ; aliquando cometes, prae se ferunt 

 & cometitce, vel cometstcin nuncupantur \" These remarks of Langius 

 are employed in illustration of a fossil coral, represented Tab. XX. 

 of the above work, and named by him, astroites stellis maximis; which 

 figure has been selected by Gmelin, as illustrative of the madrepora 

 vermicularis, but which is undoubtedly in more exact agreement with 

 the' coral which is the subject of our present examination. 



In the specimen Plate VI. Fig. 4, from Chatelor, the particular 

 characters of this coral are observable. The slightly waving rays 

 which proceed regularly from the centre, and are diffused over the flat 

 surface, yield some faint resemblance to a flower; and from the elonga- 

 tion of these rays, as may be seen in the magnified star, Plate VI. 

 Fig. 6, the idea has originated of their resemblance to the web of a 

 spider, or to the streaming tail of a comet. From these different ap- 

 pearances, which are also very strongly marked on the two opposite 

 sides of a specimen before me, have proceeded the names which this 

 fossil has acquired of rosenstein and cometstein. A considerable tract 

 of road from Bath, through Chippenham and Malmsbury, in Wiltshire, 

 is kept up by a coarse, light, brown lime-stone, formed by this madre- 

 pore. 



Madrepora vermicularis, the stars of which are formed of unequal, 

 Smooth, waved radii, several of which are bifurcated, is certainly much 



* Lithographia Helvetica. Fig. 54. f Silesia Subterranca. Tab. XVIII. Fig. 11. 

 J Historia Lapidum Figuratorum Helvetia?, &c. P. 60. 



