PLATE XLI. 



SILURIAN SPECIES. 

 Fig. 



1 — 4. Strophomena imbrex, Pander (?), var. semi(jlobosa, Dav. 1, 1 a. Wenlock 



Shale, from Rusliall Canal, near Walsall. 1 h. Longitudinal 

 section of both valves. 1 c. Shell-sculpture, enlarged. 2. A 

 more circular example, from the same locality. 3. Interior of 

 dorsal valve. Near Walsall. Mus. Midland Geol. Soc. 4. 

 A large specimen of the same valve. 



5, 6. ,, ,, ? Caradoc beds ; Craighead Quarry, near Girvan, Ayrshire. 



7. „ Dfty?, Dav. Wenlock Shale ; Buildwas, near Wenlock. 



S — 14. „ corrugatella, Dav. 8. Original specimen of Portlock's " Orthis 



corrugata!' Caradoc ; Desertcreat, Tyrone. Mus. Pract. 

 Geol. 8 a. Section. 8 h. Portion of the shell-sculpture, 

 enlarged. 9, 9 a. Specimen from the Caradoc beds of 

 the Chair of Kildare, much enlarged. 10. Complete shell, 

 seen from the dorsal valve. Caradoc ; Keisley, Westmoreland. 

 IL Ventral valve. Chair of Kildare. 12. A young shell. 

 Balcletchie, near Penkill, Ayrshire. 13. Outline of the 

 interior of dorsal valve. 14. " Orthis undulata," M'Coy, after 

 original figure, ' Sil. Foss. Irel.,' pi. iii, fig. 22. 



