Plate IX. Fig. 10, the internal structure of these bodies appear to 

 differ much from that of the preceding fossils. The zoophytes, from 

 which these, ibssils have derived their form, appear to have been hol- 

 low, and the substance, of which their surrounding part has been com- 

 posed, appears also to have differed from that of the other alcyonia, in 

 being made up, as is seen by examination of' the polished surface with 

 a magnifying lens, of minute quadrangular bodies, exactly fitting each 

 other. The cavity, which must have been answerable to the darker 

 central part in the figure, and which, in this specimen, is filled with 

 transparent yellowish flint, appears to have been of an irregular form, 

 dependent on the general shape of the including substance, and of 

 the processes, which are seen passing towards the centre. By what 

 openings the admission and the ejection of the sea water were se- 

 cured, does not appear to be discoverable. 



Plate IX. Fig. 6, represents a most perfect and beautiful fossil of 

 this species. The reticulated work has been regularly disposed over 

 its whole surface, but appears to have been removed ; it has, how- 

 ever, left regular indentations and markings, which give it a very ele- 

 gant appearance. A view of this fossil will evince, how excellently 

 adapted this kind of reticular covering must have been to accomplish 

 the alternate compression and dilatation of the substance of the alcy- 

 onium, on which its existence seems to have depended. 



Plate IX. Fig. 2, is a fossil of this same species, which is rendered 

 interesting by a considerable portion of its surface being covered by a 

 smooth coat, which, like the seeming superadded substance, described 

 in the fossil, Fig. 1, seems to agree exactly with the cortical covering of 

 the alcyoniurn. It is equally difficult to determine, whether the reti- 

 culated filaments of this, or the ramifying filaments of the former fos- 

 sil, in the original animal substance, passed under the cortical part, or 

 whether the cortical part was continuous with, and was formed, as a 

 production of the ramifying filaments, in the one instance, and of the 

 reticulated filaments in the other. 



