CRASPEDOPORUS. 



489 



GENUS 150. CRASPEDOPORUS GREV., 1863. 



Fig. Q.o.^.Crastedoporus Ralfsianus. 



Valves circular, with cellular structure, apparently divided into 

 compartments, in consequence of portions of the valve being elevated, 

 each of which portions (5 to 1 1 in number), bears an ocellus or pseudo- 

 pore at a more or less approximate distance from the margin. Central 

 portion of the valve forming a paler-coloured area, with small and less 

 distinct cells. 



This genus comprises about half a dozen species, all fossil. In the text 

 will be found (fig. 225), after Greville, Cr. Ralfsianus Gr., from the Cambridge 

 Estate, Barbadoes. I have never seen this form, but I think that the contrast 

 between the compartments is much exaggerated. 



