ORDOVICIAN AND SILURIAN BRACHIOPODA OF THE GIRVAN DISTRICT. 987 



Fig. 6. Ditto, ditto. x 2. Same horizon and locality. G. 



Fig. 7. Ditto. Internal cast of pedicle-valve. X 3. Same horizon, Ardmillan. G. 



Fig. 8. Ditto. External impression of same shell. x 3. 



Fig. 9. Ditto. Complete shell, brachial view. x 1\. Same horizon and locality. G. 



Fig. 10. Plectambonites quinquecostata (M'Coy), var. nov. sublobata. Pedicle-valve, x 4. Balclatchie 

 Group, Balclatchie. G. [This figure was accidentally misplaced on the plate.] 



Fig. 11. Plectambonites quinquecostata (M'Coy), var. nov. cylindrica. Pedicle-valve. x 2J. White- 

 house Group, Shalloch Mill. G. 



Fig. 12. Ditto. Median longitudinal section of complete shell. x 2. Same horizon and locality. G- 



Fig. 13. Ditto. Pedicle-valve (shell partly abraded) x 2. Same horizon and locality. G. 



Fig. 14. Ditto, ditto. x 2. Same horizon and locality. G. 



Fig. 15. Ditto, ditto. x 2. Same horizon and locality. G. 



Fig. 15a. Ditto. Outline posterior view of same shell. x 2. 



Fig. 16. Ditto. Complete shell, brachial side. x 2. Same horizon and locality. G. 



Fig. 17. Ditto. Pedicle- valve. x 3. Same horizon and locality. G. 



Fig. 18. Plectambonites quinquecostata (M'Coy), var. nov. depressa. Pedicle-valve. xl|. Whitehouse 

 Group, Whitehouse Bay. G. 



Fig. 19. Ditto, ditto, x 1£. Same horizon and locality. 



Fig. 20. Plectambonites quinquecostata (M'Coy), var. nov. sublobata. Pedicle-valve. x 2. Balclatchie 

 Group (conglom.), Balclatchie. G. 



Fig. 21. Ditto, ditto. x 2. Same horizon and locality. G. 



Fig. 22. Ditto, ditto, x 2. Same horizon and locality. G. 



Fig. 23. Ditto, ditto. x 3. Same horizon and locality. G. 



Fig. 24. Ditto. Interior of brachial valve, x 1|. Same horizon and locality. G. 



Fig. 25. Plectambonites ruralis, sp. nov. Internal cast of pedicle-valve. x 2. Starfish Bed, 

 Drunimuck Group, Thraive Glen. G. 



Fig. 26. Ditto, ditto. x 2. Same horizon and locality. G. 



Fig. 27. Ditto, ditto. x 2. Same horizon and locality. G. 



Fig. 28. Ditto, ditto, x 2. Same horizon and locality. G. 



Fig. 29. Ditto, ditto. x 2. Same horizon and locality. G. 



Fig. 30. Ditto. Posterior view of internal cast of pedicle-valve, x 2J. Same horizon and locality. G. 



Fig. 31. Ditto. Internal cast of broken brachial valve. x 2. Same horizon and locality. G. 



Fig. 32. Ditto. Impression of exterior of brachial valve, x 2. Same- horizon and locality. G. 



Fig. 33. Ditto. Left half of pedicle-valve. x 3. Same horizon and locality. G. 



Fig. 34. Plectambonites scissa (Salt.). Internal cast of pedicle-valve. x 3. Saugh Hill Group, New 

 lands. G. . 



Fig. 35. Ditto. Internal cast of brachial valve. x 4. Some horizon and locality. G. 



Fig. 36. Plectambonites segmentum (Ang.), var. nov. woodlandensis. Pedic-le-valve. x 3. Saugh Hill 

 Group, Woodland Point. G. 



Fig. 37. Ditto, ditto. x 3. Same horizon and locality. G. 



Fig. 38. Ditto. Complete shell, brachial side. x 3. Same horizon and locality. G. 



Fig. 39. Ditto. Impression of exterior of brachial valve. x 4. Same horizon and locality. G. 



Fig. 40. Ditto. Pedicle-valve, x 3. Same horizon and locality. G. 



Fig. 41. Ditto, ditto (with large ears), x 3. Same horizon and locality. G. 



Fig. 42. Plectambonites sericea (Sow.), var. nov. albida. Pedicle and brachial valves in juxtaposition. 

 x 4. Whitehouse Group, Whitehouse Bay. G. 



Fig. 43. Ditto. Pedicle-valve, x 4. Same horizon and locality. G. 



Fig. 44. Ditto, ditto, x 4. Same horizon and locality. G. 



Fig. 45. Ditto. Brachial valve, x 3. Same horizon and locality. G. 



Fig. 46. Ditto. Internal cast of brachial valve. x 5. Same horizon and locality. G. 



TRANS. ROY. SOC. EDIN., VOL. LI, PART IV (NO. 26). 140 



