122 POTEEIOCBINrD^ PENTACEINUS. 



The articulating facets of the columnar joints differ from those of the other Pentacrines. 

 The crenulated floriform ridges in the Millerii occupy the entire margin, following the 

 sinuosities of the column with unerring regularity, but they are not prolonged so far 

 inwardly towards the central axis as in tlie other species. Beautiful as are all tlie columns 

 of the Pentacrines, none excel this in the admirable arrangement of the striae, which 

 strengthened and at the same time allowed the column to move laterally in every direction. 



The claspers are round, long, and delicately fine. They occur in series of five each, 

 but at shorter intervals than in the typical species. 



Miller appears to have been aware of the occurrence of this Pentacrinus, in the Inferior 

 Oolite of Dundry, but from the fragmentary state in which it had been obtained when 

 he wrote his Natural History, he was unabled to ascertain its specific characters. Since 

 he terminated his researches, several well preserved specimens have been procured, 

 figures of which will found in PI. 16. 



This crinoid has long been known in our museums as the P. Milleri. Dr. Gold fuss 

 has figured and described it under the name of P. scalaris, but as it has been dedicated 

 to Miller, its first discoverer, by the sanction of most British Palaeontologists, we have 

 retained the specific name which has been so long familiar to us. 



The P. Millerii is only known in the Britisli Isles as a characteristic fossil of the 

 Lower Oolite, but Goldfuss has noticed its occurrence in the marly beds of the Jura 

 formation,'which beds the Doctor considers as equivalents of the Oxford Clay of British 

 Geologists. These marly beds occur at Baireuth, Banz, Amberg, and Boll. 



If these beds are the true equivalents of the Oxford Clay, this Pentacrinus must have 

 continued to exist to the eastward of Britain some time after it became extinct in the 

 West. 



5. Species. Pentacrinus subbasaltiformis. (Aliller.) 

 Plate 16, Figure 2. 



The column of this species is less angular than that of the P. ba salt i/or mis, and the 

 radiating floriform markings on the articulating surfaces of the joints somewhat different 

 and less strongly marked. 



The only portion known of this Pentacrinus is the column, therefore its more general 

 characters still remain concealed among the entombed organic treasures of a bygone period. 



