PASCEOLUS, CYCLOCRINUS, AND NIDULITES. 



I8 7 



aspect of being divided into a series of hexagonal or pentagonal 

 areas of very regular form and size (fig. 73, h). Each of these areas 

 has the form of a shallow cup-shaped depression, the lower or convex 

 end of which is directed towards the interior of the fossil, and, 

 according to Hinde, is perforated centrally by a small rounded aper- 

 ture which leads into the central cavity of the organism. According, 

 however, to Ferdinand Roemer, whose figures are here reproduced 

 (%• 73> /* an d < ^), each of these cup-like plates terminates internally 



®mm 



Fig. 73.— «, Pasceolus Halli, of the natural size (after Billings) ; b, Pasceolus globosits, of the 

 natural size (after Billings) ; c, Pasceolus (?) tucllijtua, of the natural size (after Salter) ; d, Four 

 of the integumentary plates of the same, enlarged ; e, Cyclocrimis Spaskii, of the natural size 

 (after Ferd. Roemer) ; /, Part of a vertical section of the same ; g, Part of the last, showing the 

 structure of the integument, enlarged ; h, Part of the mould of the inner surface, enlarged ; 

 i, Diagram of a vertical section of Cyclocriuus (Xidulites)favus, showing the form of the body 

 and integumentary plates, and the supposed peduncle (original). All the specimens are from the 

 Silurian, except b, which is from the Ordovician. 



in a small pillar, and the genus is hence compared by this distin- 

 guished palaeontologist with Receptaculites. Dr Hinde, on the other 

 hand, does not recognise in Cyclocrinus any features of resemblance 

 to Receptaculites ; and considers that the genus is identical with 

 Nidulites. 



The present writer has not had the opportunity of studying the 

 genus Cyclocrinus, and is therefore unable to express a positive 



