Fig. 



20. Chonetes Hardrensis. C. sulcata, M'Coy. From the original specimen, Are- 



naceous slate, Bruckless. Dunkeneely, Ireland. Col- 

 lection of Sir R. Griffith. 



21. „ „ C. volva, M'Coy. From the original and other exam- 



ples in the collection of Sir R. Griffith, Carboniferous 

 limestone of Millecent, Ireland. 



22. ,, ,. A small variety, from the shales above the Hosie lime- 



stone, South Hill. Campsie, Stirlingshire, Scotland. 



23. ,, „ C.yibberula, M'Coy. From the original figure. 



24. ,, „ C. subminima, M'Coy. From the original figure. 



25. „ ,, C. perlata, M'Coy. From the original specimen, in 



the collection of Sir R. Griffith. 



20. „ serrata, M'Coy. From the original specimen, Carboniferous lime- 



stone, Millecent, Ireland. 



27. „ tuberculata, M'Coy. From the original specimen, Carboniferous 



limestone, Millecent, Ireland. 



28. ,, Buchiana? or crassistria, M' Coy. From the original specimen, Bun- 



doran, Ireland. 



29. „ papyracea, M' Coy. From the original specimen, Ireland. 



