PLATE XXXIX. 



SILURIAN SPECIES. 

 Fig. 

 1 — 21. Strophomena rhomboidalis, Wilckens. 1. Exterior of a very large-winged 



specimen. Wenlock Limestone, Dudley. 2 — 9. 

 Different forms and ages. Erom Dudley, Benthal 

 Edge, the Pentland Hills, &c. 8 and 9 show the 

 small circular foramen. 3 3 is a longitudinal section 

 of both valves. 4. From Dorraington Wood, Wool- 

 hope. Mus. Pract. Geol. 10. Interior of the dorsal 

 valve. Wenlock Limestone; Abberley. Worcester 

 Museum of Nat. Hist. 11, 12. Another specimen 

 from Dudley. 13. Internal cast of the dorsal valve. 

 14. Interior of a ventral valve. Dudley. 15. Another 

 winged example. British Museum. 16. A Gothland 

 specimen, showing impressions of oral arms. 17. 

 Internal cast of a ventral valve from Woolhope (?) 

 beds ; Bogmine, Shelve. Mus. Pract. Geol. 18. 

 From Ludlow Rock ; Freshwater. 19. "■ Lept. tenui- 

 striata" Sow., ' Sil. Syst.,' pi. xxii, fig. 2 a. 20. 

 From Llandovery Rock J Penhill, Ayrshire. 21. From 

 Caradoc beds ; Bala Lake. Mus. Pract. Geol. 



22. „ deUoidea, Conrad (?) = " Stroph. semiovalis," M'Coy, ' Sil. Foss. 



Irel.,' pi. iii, fig. 6 ; referred to St. deUoidea by the 

 same author in ' Brit. Pal. Foss.' 



23, 24. „ ,, var. undata, M'Coy, after figures in ' Brit. Pal. Foss,,' 



pi. i H. Caradoc beds. 23. From Llwyn-y-Ci. 



