PLATE XXVII. 



Fig. 1. — Sedgwickia ovata. A right valve, showing the characteristic markings 

 in front. From the Redesdale Ironstone. My Collection. (Page 281.) 



Fig. 1 a. — Sedgwickia ovata. The same shell, showing the hinge with a small 

 median cardinal tooth. 



Fig. 2. — Sedgwickia ovata. A left valve with the shell removed posteriorly, 

 showing the posterior adductor muscle-scar and pallia! line. Same locality. My 

 Collection. (Page 281.) 



Fig. 3. — Sedgivickia ovata. A right valve with most of the test preserved. 

 Same locality. My Collection. (Page 281.) 



Fig. 4. — Sedgwickia ovata. A young specimen of the left valve. Same 

 locality. My Collection. (Page 281.) 



Fig. 5. — Sedgwickia suborbicularis. A testiferous left valve. From Pot Metal 

 Plantation, Kirkaldy. In the Collection of the Geological Survey of Scotland. 

 (Page 284.) 



Fig. 6. — Sedgwickia suborbicularis. A full-grown left valve. From Inverteel 

 Quarry, Kirkaldy. Same Collection. (Page 284.) 



Fig. 7. — Sedgwickia suborbicularis. A young example. From Hope Quarry, 

 Pathhead, Haddingtonshire. Same Collection. (Page 284.) 



Fig. 8. — Sedgivickia suborbicularis. A testiferous right valve, showing erosion 

 of the umbo. The same locality and Collection as Fig. 6. (Page 284.) 



Fig. 9. — Sedgwickia attenuata. M'Coy's type. A right valve. Preserved in 

 the Griffith Collection of the Museum of Science and Art, Dublin. (Page 285.) 



Fig. 10. — Sedgwickia gigantea. The type of M' Coy's Dolabra secur ij 'ormis. A 

 cast of both valves. Same Collection. (Page 278.) 



Fig. 11. — Sedgwickia attenuata. The cast of a right valve. From Calcareous- 

 grit, Pulse Hill, near Marsden. My Collection. (Page 285.) 



Fig. 12. — Sedgwickia attenuata. The cast of both valves. Same locality. My 

 Collection. (Page 285.) 



Figs. 13, 14. Sedgwickia attenuata. Casts. Same locality. My Collection. 

 (Page 285.) 



Fig. 15. — Edmondia rudis. A perfectly preserved cast of the interior. From 

 the Carboniferous Limestone of Castleton, Derbyshire. In the Collection of 

 Mr. J. Barnes, F.G.S. (Page 302.) 



Fig. 15 a. — Edmondia rudis. The same specimen viewed from above, showing 

 the grooves of the lamellse attached to the hinge-plate. 



Fig. 16. — Edmondia unionif ormis. From the Carboniferous Limestone of 

 Tournay, Belgium, showing the edentulous hinge, 16 a, and at 16 k the hinge 

 viewed from below. (Page 291.) 



