PLATE XL 



FIG. 1. An alcyonite formed of plicae, connected by transverse processes thinly disposed. 



2. An alcyonite, from Switzerland, of a singular form, having in its superior part a 



large central opening. 0, represents the magnified appearance of its structure 

 as obtained by polishing a part of its surface. 



3. An alcyonite, the plicae of which are more frequently connected by ramifying 



fibres, or tubuli, than those of Fig. 1, as is represented on the superior part of 

 the fossil. 



4. A flint, from Wycombe Heath, containing an alcyonite, which is of a purple hue, 



and is surrounded by its original covering, from which, numerous tubuli 

 may be seen passing into the more internal part. 



5. Part of a funnel-formed alcyonite, from France. The labours of the polype may 



be traced on the edge at its superior part. 



6. An alcyonite, in which the plica? are very frequently connected by transverse 



processes, leaving quadrangular spaces. 



1. A fungiform alcyonite, the structure of which much resembles that of Fig. 6. 



8. A ficoid alcyonite, imbedded in a flint. The white matter which immediately 

 surrounds the alcyonium, appears to be its original cortical covering, as is 

 observable in the fossil, Fig. 4. On the back part of this beautiful fossil is 

 a purplish spot, where the pedicle passed out, produced by the transparent 

 dark flint acquiring a tinge of red from the alcyonite : explaining the reason of 

 the purple hue in the alcyonite, Fig. 4. 



VOL. 11. R R 



