PLATE VI. 



(Carboniferous Species.) 



Fig. 



1. Spirifera bisulcata, Sowerby, var. semicircularis, Phillips. From the original 



illustration, ' Geol. of Yorkshire,' vol. ii, tab. ix, fig. 15. 

 Bolland. 



2. — — var. semicircularis. Bolland. Collection of Mr. Muschen. 



3 — 4. — — In the collection of Professor Phillips, labelled Sp. semicircu- 



laris. Bolland. 



5. — — From Twiston, Lancashire. Collection of Mr. Parker. 



6 — 9. — — From the original type specimen, ' Min. Con.,' tab. 494, fig. 1. 



Collection of Mr. J. de C. Sowerby. 



10. — — A very large example from Dovedale, Derbyshire; in the 



Museum of Practical Geology. 



11. — — A specimen with very large ribs, from the Wensleydale district, 



Yorkshire. Collection of Mr. E. Wood. 



12. — — From Derbyshire ; several of the ribs are bifurcated. 



13. 14. — — From the specimen, 'Min. Con.,' tab. 265, fig. 3, erroneously 



described by Sowerby as Sp. tric/onalis. 



15. — — From Craigenglen (Campsie), Scotland. Collection of Mr. 



Young. 



16. — Ventral valve, from Barrhead, Scotland. Collection of Mr. 



A. Cowan. The fine imbricated lines which cover the costae 

 are beautifully seen in this example. 



17. — — From a specimen in the collection of Mr. J. de C. Sowerby. 



Derbyshire. 



18. — — A very transverse young specimen, from the Wensleydale dis- 



trict, Yorkshire. Collection of Mr. E. Wood, of Richmond. 



19. — — A very transverse specimen, in the collection of Dr. Reed, of 



York. Yorkshire. 

 20 — 22. Spirifera crassa, De Koninc/c= Brachythjris planicosta, M'Coy. This is the 



original specimen, imperfectly illustrated in the ' Synopsis 

 of the Carboniferous Fossils of Ireland,' tab. xxi, fig. 5. 

 Loc. Mullaghfin, Duluk, Ireland. 



