358 
Mr. Toulrnin Smith on the Classification 
remarkable structure as must excite the astonishment and ad- 
miration of every earnest inquirer. 
Fig. (). 
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 Flustrce^. 
Others have amused themselves by discovering analogies to the 
foliaceous s])onges. llemains 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 Asterice. 
The form in which the species is necessarily most usually found 
* Ante, p. 7-1, note*. 
