Fre. 
|—9. 
10—11. 
]2—13. 
14. 
15—16. 
17—19 a. 
20. 
PLATE XXVII. 
SILURIAN SPECIES. 
Orthis elegantula, Dalman. 1—6. Different forms, from the Wenlock Lime- 
9? 
? 
stone of Dudley and near Walsall. 7a. Interior of the 
ventral. valve, enlarged. 74. Interior of dorsal valve. 
8. Interior of dorsal valve seen from the hinge-line, 
showing the projecting cardinal plates and process. 9 
and 9a. Internal casts, enlarged ; from Wenlock Shale ; 
Slate Mill, Pembrokeshire. Mus. Geol. Survey. 
basalts, Dalman (according to Lindstrém)._ Wenlock Shale; Falfield; 
near Tortworth. 
canaliculata, Lindstrom. Aymestry Limestone ; Sedgley, near Wolver- 
hampton. 
elegantula, vay.? Bala Limestone; Blaeny Crom, Denbighshire. Mr. 
Davies’ Collection. 
hybrida, Sow. Wenlock Limestone; Dudley. 16. Interior of dorsal 
valve, enlarged. 16. Interior of ventral valve, enlarged. 
crassa, Lindstrom. 17. Wenlock Limestone; Garcoed, near Usk. 
18. Wenlock Limestone, Malverns. 19. Interior of dorsal 
valve, enlarged ; Lower Ludlow ; near Martley. 18 and 
19. In Coll. Geol. Survey. 
3 Species not determined ; supposed to be a very large var. of 
O. hybrida ; from Wenlock Limestone ; near Walsall. 
