PLATE IX. 



FIG. 1. A flint, from a gravel-pit. In this fossil are seen the ramifying filaments round 

 the central opening ; with the cortical part, under which these filaments seem 

 to pass. 



2. Is a silicious alcyonite, the surface of which is reticulated, except where part of 



its original external coat remains. The fossils depicted, Fig. 6, 9, and 10, 

 appear to be of the same species. 



3. A fig-like alcyonite, from Switzerland. In this fossil the pedicle, or organ of 



attachment, as well as its superior opening, is very evident. 



4. An alcyonite, from Wiltshire, bearing somewhat of the form of Alcyonium Ficus. 



5. A very perfect alcyonite, from the neighbourhood of Saumur, having four open- 



ings in its superior part, and the remains of several root-like processes. 



6. A silicious alcyonite, beautifully marked, externally, with various risings and in- 



dentations. 



7. A polished transverse section of a silicified alcyonium, resembling the supposed 



petrified nutmeg of Volkmann and Scheuchzer. In this specimen the regular 

 arrangement of the muscular fibres, or tubuli, is seen. 



8. A fig-formed alcyonite, of the same species with that which is imbedded in flint, 



Plate XI. Fig. 8. 



9. A calcedonic alcyonite, possessing a reticulated surface. 



10. A longitudinal section of the preceding fossil, shewing its internal structure. 



11. The external superior part, with the opening of a ficoidal alcyonite. 



12. A section of a ficoidal alcyonite, with fibres ramifying through its substance. 



13. The polished transverse section of the ficoidal alcyonite, Fig. 11, shewing in the 



centre appearances like the receptacles for the pips of fruits. 



14. A small calcareous spongite, or alcyonite, from Switzerland. 



15. The appearance yielded in consequence of subjecting a similiar fossil to the action 



of diluted muriatic acid. 



