PLATE XVII. 



Figs. 1 and 2. — [Modiola] Macadami, var. subparallela. From the Ballycastle 

 Coal-measures, co. Antrim. In the Collection of Mr. Joseph Wright of Belfast. 

 (Page 88.) Since page 88 was printed I have discovered from a fine specimen in 

 the Belfast Museum, showing the hinge, that the shells from Ballycastle now 

 figured are uot of the genus Modiola, but belong to the Anthracomyas. 



Fig. 3. — Anthracomya subcentralis. The roof of the Four-foot Coal, Bilboa, 

 Castlecomer. Collection of the Geological Survey, Jermyn Street. (Page 109.) 



Figs. 4 and 5. — Anthracomya subcentralis. Bilboa, Queen's Co. Collection of 

 the Geological Survey of Ireland, Dublin. (Page 109.) 



Figs. 6 and 7. — Anthracomya Williamsoioi. Same locality and Collection. 

 (Page 99.) 



Figs. 8, 9, 10, 12 — 15. — Naiadites modiolaris. Showing the striated hinge- 

 plate ; obsolete anterior hinge-tooth and trifid anterior adductor scars. From 

 the Shale above the Bowling Alley Coal, Hanley and Bucknall Colliery, North 

 Staffordshire. My Collection. (Page 131.) 



Fig. 11. — Naiadites? sp. A portion of the shell magnified to show prismatic 

 structure, from a specimen sent me by Dr. John Young of the Hunterian Museum. 

 (Page 131.) 



Figs. 10, 1G a, 18. 18 a. — Naiadites modiolaris. Two views of two casts showing 

 anterior and posterior muscle-scars and the mantle-line. Roof of the Hard Mine 

 Coal, Adderley Green, North Staffordshire. My Collection. (Page 131.) 



Fig. 17. — Naiadites modiolaris. To show the flattened right valve. Same 

 locality and Collection. (Page 131.) 



Figs. 19, 20. — Naiadites modiolaris. To show variation in contour. Same 

 locality and Collection. (Page 131.) 



Fig. 21. — Naiadites modiolaris. From the locality whence the types were 

 procured. Coalbrookdale. My Collection. (Page 131.) 



Figs. 22 — 20. — Naiadites modiolaris. Testiferous specimens showing lines of 

 growth and variation in shape. Roof of the Hard Mine Coal, Adderley Green, 

 North Staffordshire. My Collection. (Page 131.) 



Figs. 27 — 30. — Naiadites modiolaris. A series of young specimens from the 

 same locality. My Collection. (Page 131.) 



Figs. 31 — 38. — Naiadites triangularis. A series showing the changes resulting 

 during growth. From the same locality. My Collection. (Page 135.) 



