AGES OF NATURE. 



231 



(Fig. 162,) an extinct type of animals, protected by a sheath, 

 and terminating in a conical body, somewhat similar to the 

 bone of the Sepia, which 

 commonly is the only 

 part preserved, 



487. The variety is 

 not less remarkable 



among 



Fig. 162. 



the Radiates. 



There are to be found representatives of all the classes ; 

 even traces of Jelly-fishes have been made out in the 

 slate of Solenhofen, in Bavaria. The Polyps were very 

 abundant at that epoch, especially in the upper stages, one 

 of which has received the name of Coral-rag. Indeed, 

 there are found whole reefs of corals in their natural po- 

 sition, similar to those which are seen in the islands of the 



a 



Pacific. Among the most remarkable types of stony Polyps 

 may be named the fan- like Lobophyllia, (L.flabellum, a,) 

 and various forms of tree-corals, Lithodendron pseudosty- 

 llna, &.) But the greatest variety exists among the Echino- 

 derms. The Crinoids are not quite so numerous as in 

 former ages. Among the most abundant are the Pentacri- 

 nus, (c.) There are also Comatula-like animals, that is to 

 say, free Crinoids, (Pterocoma pinnata, d.) Many Star- 

 fishes are likewise observed in the various stages of this 

 formation. Finally, there is an extraordinary variety of 



