93 



remarkable structure as must excite the astonishment and ad- 

 miration of every earnest inquirer. 



Fig. O. 



Few fossils have given rise to more varied conjecture than 

 this. A fragment of a specimen found in an unusual con- 

 dition by Dr. Mantell was originally figured by him under the 

 name of Ventriculites quadrangular is. He subsequently aban- 

 doned that view, showing that it had been adopted without the 

 guide of any definite principle, and, for what reason it is diffi- 

 cult to imagine, and none is stated, placed it among Flustrte*. 

 Others have amused themselves by discovering analogies to the 

 foliaceous sponges. Remains both in chalk and flint, which had 

 apparently escaped Dr. MantelFs notice, or whose connexion 

 with his figured specimens was at any rate not perceived by him, 

 have even been placed by collectors among the Asteria. 



The form in which the species is necessarily most usually found 



* Ante, p. 2, note*. 



