IPILEOLUS. 



by their discoverer. We now proceed to give their specific 

 characters : 



1, P. plicatus^ testA, obtuse conicA^ plicis radiantibus ex 



vertice ad marginem decurrentibus; margine irre- 

 gulariter crenulato : parte centrali disci inferi 

 divisEi. 



2. P. laevis, testd planulat^^ margine integro. 



Obs.— The radiating plicae on the outside of P. pli- 

 catus, is not the only character by which it is distin- 

 guished from P. laevis; this latter is flatter, and the 

 cushion like center of the inferior disk is entire. 



Both these species are fossil; they occur together in 

 the coarse upper layer of Oolite, above which lies the 

 Bradford Clay, containing Apiocrinites rotundus of Miiller, 

 at Anclilfe, and have also been found in a similar stratum 

 at Charter-house Hinton, in Somersetshire ; where they 

 are associated with a minute Nerita, and many other 

 marine fossil shells, several of which we have only seen 

 from this identical bed. 



Fig. 1 • Pileolus plicatus, to show its elevation. 



2. 



upper surface. 



3. 



lower surface. 



4. 



' the same magnified. 



5. 



laevis, to show its elevation. 



6. 



upper surface. 



7. 



lower surface. 



8. 



the same magnified. 



