THE LAMELLIBRANCHS OF THE SILURIAN EOCKS OF GIRVAN. 547 



Plate lit. 



Figs. 1, la,b. Gosseletia ponder osa, three views, cast of the interior. Page 500. 



Fi<*. 2. ,, antiqua, showing the left valve. Page 500. 



Fig. 3. „ ,, showing the right valve. Page 500. 



Fig. 4. Opistkoptera transversa, a left valve. Page 495. 



Fig. 5. Ctenodonta dissimilis, right valve. Page 522. 



Fig. 6. „ ,, left valve. Page 522. 



Fig. 7. „ ,, showing hinge plate. Page 522. 



Fig. 8. ,, lingualis, a bivalve example. Page 522. 



Fig. 9. „ ,, the right valve. Page 522. 



Figs. 10-11. Ctenodonta triangularis. Page 523. 



Figs. 12, 13, 14. „ aff. transversa. Page 523. 



Figs. 15, 16, 17. ,, regularis. Page 524. 



Figs. 18, 19. ,, obliqua, right valves. Page 524. 



Figs. 20, 21, 22. „ eastnori. Page 525. 



Fig. 23. ,, semitruncatus, a perfect example. Page 525. 



Fig. 24. ,, ,, a right valve showing the hinge plate. Page 525. 



Fig. 25. „ ,, a compressed specimen. Page 525. 



Figs. 26, 27. Paheoneilo sinuatus. Page 527. 



Fig. 28. ,, antiqua, a left valve. Page 526. 



Fig. 29. Nucula levata, a left valve. Page 517. 



Figs. 30, 31, 31a. Nucula levata, a perfect example. Page 517. 



Fig. 32. „ varicosa, a left valve. Page 518. 



Fig. 33. ,, ,, showing the hinge teeth. Page 518. 



Figs. 34-37. „ „ . Page 518. 



Plate IV. 



Fig. 1. Nuculana lobata, a perfect specimen, view of left valve. Page 519. 

 Fig. 2. ,, „ a complete example, view of right valve. Page 519. 



Figs. 3, 3a. „ ,, a cast of the interior; Fig. 3, a cast of hinge plate. Page 519. 



Fig. 4. „ imbricala, a left valve. Page 519. 



Fig. 5. „ „ a right valve. Page 519. 



Fig. 6. „ ,, a cast of the interior showing hinge plate. Page 519. 



Figs. 7, 7a. ,, ,, the right and left valves of the same shell. Page 519. 



Fig. 8. ,, concentrica, a specimen showing both valves. Page 520. 



Fig. 9. „ ,, the left valve. Page 520. 



Fig. 10. „ eurta, a left valve. Page 521. 



Fig. 11. ,, ,, a right valve, compressed. Page 521. 



Figs. 12, 12a. „ „ cast of the interior showing hinge plate. Page 521. 



Fig. 13. „ „ internal cast showing hinge plate. Page 521. 



Figs. 14, 14a. ,, ,, a specimen showing both valves. Page 521. 



Fig. 15. Glidophorus ])lanulatus, a left valve. Page 528. 

 Fig. 16. Cucullella antiqua, showing multidenticulated hinge. Page 545. 

 Fig. 17. Ct/rtodonta gibbusa, left valve with cast of hinge plate. Page 512. 

 Fig. 18. „ Billingsiana, a left valve with cast of hinge plate. Page 512. 



Figs. 19, 19a. „ transversa, left valve with view of the posterior part of the hinge plate. Page 513. 



Fig. 20. „ „ a right valve. Page 513. 



Fig. 21. „ penkhillense, both valves. Page 511. 



Fig. 22. Pararca tenulineata, a left valve. Page 515. 

 Fig. 23. Dualina elegans, the right valve. Page 533. 



Figs. 24, 24a. Goniophora antiqua, a bivalved example, with view of the hinge line. Page 539. 

 TRANS. ROY. SOC. EDIN., VOL. XLVII. PART III. (NO. 18) 80 



