PLATE X. 



(Carboniferous Species.) 



1 — 7. Spikifeka pinguis, Sowerhy. Different specimens and ages. From Millecent, 



Ireland. 

 S — 12. — — var. rotundata, Sow. (not Martin) = subrottindata, M'Coy. 



From Millecent, Ireland, fig. 9. From Yorkshire. 



