PLATE VIII. 



(Carboniferous Species.) 



Fig. 

 1 — 4. Spirifera distans, Sowerby. From the original example, ' Min. Con.,' tab. 494, 



fig. 3. Ireland. Collection of Mr. J. de C. Sowerby. 

 5 — S. — — Ireland. 



9,10. — — In the collection of Professor Tennant. Ireland. 



11 — 14. — — In the collection of Professor L. de Koninck. Millecent, 



Ireland. 



15. — — Ireland. Figs. 1 to 17 exemplify the different states of 



development and incurvation of the beak and area, &c. 



16. — — A very wide example. Millecent. 



17. — — This figure shows the development attained by the dental or 



rostral plates (s) in the ventral valve. 



18. — bicarinata, M'Coy. ' Synopsis of the Carboniferous Limestone 



Fossils of Ireland,' pi. xxii, fig. 10. 



19. — ctjspidata, Martin} From Millecent. Small specimen. 



20. — — From a gritty sandstone near Kendal. 



21 — 23. — — A large example from Ireland. In the collection of Mr. Reed, 



of York. 

 24. — — A very large specimen from the Black Rock, Cork, Ireland. 



1 At p. 45, I stated that no specimen of Sp. cuspidata I bad hitherto been able to examine possessed 

 its deltidium, and that I considered it was in all probability not perforated by a circular foramen, as in true 

 types of the sub-genus Cyrtia. Subsequently, however, Mr. J. P. Woodward showed me the internal cast 

 of the ventral valve of a specimen in the British Museum, thought to have belonged to Sp. cuspidata, and 

 derived from the dolomitic Carboniferous limestone of Breedon hill (pi. ix, figs. 1 and 1 a) in which there 

 is evidence that the deltidium was in reality perforated by a circular foramen, as in Cyrtia. 



