103 
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 fossils 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 secured 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, however, 
left regular indentations and markings, which give it a very elegant 
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 alcyonium, 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 cortical covering of 
the alcyonium. 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. 
